Surface Treatment Methods Research Articles

Laser-induced surface reconstruction to enhance interfacial bonding reliability of CFRP/titanium hybrid joints

Adhesive bonding is widely used in aeronautical carbon fiber-reinforced polymer (CFRP)/titanium (Ti) alloy hybrid structures to satisfy the demands of high-strength and lightweight. The physicochemical properties of adherend surfaces significantly impact the bonding performance. In this study, laser-induced surface reconstruction (LISR) was designed for the reliable joining of Ti alloy and CFRP. A three-level-three-factor central composite design (CCD) approach-based response surface methodology (RSM) analysis was applied to statistically specify parameter optimization of the laser energy output. Surface morphology and wettability of CFRP ablated were studied. Chemical compositions were determined by X-ray photoelectron spectroscopy (XPS). Tensile-shear tests were performed, and fractured surfaces were analyzed. The tensile shear strength with LISR process has been improved by 19.1%, in comparison with that of mechanical grinding treatment. The cross-like texture based on designed geometric configuration was fabricated without damaging the underlying fibers, thus increasing the surface roughness and contact area at interface. The wettability transition mechanism was investigated, demonstrating that the hydrophilicity of reconstructed surfaces primarily attributes to the more polar groups (C–O, CO, etc.) on CF surfaces. This study provides a reliable surface treatment method for fabricating high-performance composite structures by adhesive bonding.

Three-Dimensional Optical Study on the Effects of Microwave Glazing on Surface Roughness of Zirconia-Reinforced Glass Ceramic.

BACKGROUND This 3-dimensional (3D) optical study aimed to evaluate the effects of microwave glazing on the surface roughness of zirconia-reinforced glass. Glazed surfaces of ceramic provide a smooth and esthetically superior restoration. There are many methods of glazing. However, this study aims to evaluate the effect of microwave glazing on ceramic restorations over conventional oven and hand polishing. MATERIAL AND METHODS A sample size of 90 ceramic material tiles was derived according to the standard sample size formula. The 3 dental ceramics used were IPS e.max CAD (lithium disilicate ceramic; IvoclarVivadent), Suprinity (zirconia-reinforced lithium silicate; VITA Zahnfabrik), and Celtra Duo zirconia-reinforced lithium silicate; Dentsply Sirona). Each group was further divided equally to undergo conventional oven glazing, hand polishing, and microwave glazing. The final glazed surfaces were then evaluated for surface roughness with the Ra parameter, using a Contour GT 3D Optical Microscope (Bruker) and 3D non-contact surface metrology with interferometry. RESULTS The ANOVA test for intergroup comparison showed microwave glazing was a significantly better glazing method than conventional oven and hand polishing (P<0.05). A statistically significant difference was shown between conventional and microwave glazing; however, the difference was greater between conventionally glazed and hand-polished specimens. Furthermore, a highly significant difference between microwave-glazed and hand-polished specimens was observed. CONCLUSIONS Results showed that irrespective of the ceramic, microwave-glazed ceramics were better than traditional oven-glazed ceramics, and hand-polishing resulted in a rougher surface than glazing. Irrespective of the surface treatment methods, IPS e.max CAD ceramic showed a relatively smoother surface than did Suprinity and Celtra Duo.

Effect of Er:YAG laser surface treatment on surface properties and shear-bond strength of resin-cement to three translucent zirconia: an in-vitro study

Achieving optimal bonding to translucent zirconia poses certain challenges as there is no consensus on ideal surface treatment method. Therefore, the aim of present investigation is to evaluate effect of Er:YAG laser treatment on wettability, surface roughness and shear-bond strength of three Yttrium oxide-stabilized zirconium-oxide polycrystal translucent zirconias. 120 specimens (n = 40/zirconia type) were prepared from three commercially-available translucent zirconias (Dentsply Sirona, USA); Translucent, High-Translucent and Ultra-Translucent zirconia. Specimens were sub-divided (n = 20/surface-treatment) into control and Er:YAG laser surface-treated groups. Regarding water wettability test; goniometer was used to measure contact angle before and after laser treatment. Surface roughness was measured using atomic force microscope. For shear-bond strength (SBS) test; the control group was sandblasted. All resin-bonded zirconia specimens were thermocycled for 5000 cycle and subjected to shear force using universal testing machine with 0.5 mm/min crosshead-speed. Results were statistically analyzed using two-way-analysis-of- variance (p ≤ 0.05). There was significant decrease in average contact angles (p-value < 0.001) in all zirconia groups after laser treatment. For roughness test; insignificant difference in average Ra in Translucent zirconia group. However, significant increase in mean Ra was revealed after laser treatment for High and Ultra-Translucent zirconias. For SBS test, results revealed insignificant difference in average bond strength after laser treatment in Translucent and High-translucent zirconia groups. Significant increase in mean bond strength of Ultra-Translucent zirconia was recorded. Er: YAG laser treatment significantly affected surface properties and shear-bond strength of Ultra-Translucent zirconia. Er:YAG laser irradiation may be a promising zirconia surface treatment method.Graphical

Superficially activating strategies to elevate the supercapacitor performance of nano-cube nickel cobalt-Prussian blue

Prussian Blue Analogs (PBA) has good application potential in supercapacitors due to their unique microstructure characteristics. Nevertheless, the limited conductivity of these materials poses a significant obstacle to their widespread application as electrodes in supercapacitors. Herein, the conductivity of NiCo-PBA is enhanced through the implementation of three surface treatment methods, namely sulfidizing, selenizing and phosphating, and then the explicit electrochemical performance of NiCo-PBA was elevated. In addition, the P-NiCo-PBA//AC ASC occupies the best energy density (48.90 Wh kg−1/42.16 Wh kg−1) at a certain power density (1947.38 W kg−1/9545.10 W kg−1) compared to the NiCo-PBA//AC ASC, S-NiCo-PBA//AC ASC and Se-NiCo-PBA//AC ASC, and the specific capacitance retention rate of P-NiCo-PBA//AC ASC after 10,000 cycles is 88.25%. The phosphating strategy outperforms sulfidizing and selenizing strategies in enhancing the performance of nanocube-like NiCo-PBA supercapacitors. The accomplishment significantly broadens the potential applications of PBA-based materials as electrodes for supercapacitors.

Rapid surface patterning to strengthen adhesive bonding of carbon fiber reinforced polymer by spatial shaping femtosecond laser

Carbon fiber reinforced polymer (CFRP) have become gradually important in the aerospace industry due to their outstanding strength-to-weight ratio. However, traditional mechanical surface treatment methods are challenging to apply to CFRP because of their anisotropic and nonhomogeneous properties. Femtosecond laser offers unique advantages for surface treatment, as it allows processing with very low thermal load due to the extremely short interaction time. This study investigates the effect of different surface structures resulting from surface treatment using a femtosecond laser on adhesive properties of CFRP. The experimental results show that: 1) beam shaping can be realized by using the plano-convex cylindrical mirror, which improves the quality of laser processing and greatly improves processing efficiency. It only takes 20 s to complete the laser processing of a 1 cm*1 cm area, which increases the work efficiency by 49 times. 2) pre-bonding surface treatment significantly enhances the tensile shear strength of the single lap joint, and the shear strength of samples with low spatial frequency LIPSS (LSFL) (14.57 ± 1.58 MPa) is 2.96 times higher than that of the untreated sample (US) (4.92 ± 1.34 MPa). 3) LSFL structure exhibits the best results, because the surface of CFRP with LSFL exhibits a relatively higher surface polarity and surface energy. This study provides an efficient, high-precision, and low-damage surface treatment method for preparing CFRP for adhesive bonding, which may promote the application of femtosecond laser technology in difficult-to-process composite materials and provide new methods and technical support for its application in aerospace, vehicle manufacturing, and other fields.

Impact of plasma-modified pretreatment on the tensile properties of carbon fiber-reinforced epoxy composites

Abstract Low-temperature jet plasma modification technology is a surface treatment method designed to enhance the surface properties of materials without causing severe thermal damage. This technique modifies surface characteristics by creating plasma and utilizing ions and reactive groups within the plasma to chemically interact with the material’s surface. In this study, surface modification of carbon fibers was carried out by using low-temperature jet mixed oxygen plasma technology at treatment speeds of 25 mm/s, 50 mm/s, 100 mm/s, and 200 mm/s. Following the modification process, carbon fiber-reinforced epoxy composites were fabricated by using a hand-lay-up technique. Subsequently, the tensile properties of the carbon fiber composites were tested to evaluate the impact of the plasma treatment on their mechanical performance. The experimental results demonstrated a significant enhancement in the tensile properties of the composites when the carbon fibers were pretreated at a rate of 50 mm/s. This enhancement was evidenced by an impressive increase of 82.38% in tensile strength and 30.96% in tensile modulus compared to untreated samples. This signifies that low-temperature plasma treatment has a beneficial effect on enhancing the surface properties of carbon fibers and improving the performance of composites. This finding provides substantial support for the extensive application of carbon fiber composites.

Investigations on structure and properties of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) reinforced by diss fibers: Effect of various surface treatments

The paper reports some experimental results on the effect of different chemical modifications of Diss fibers on the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biocomposites involving alkaline, combined alkaline/peroxide and combined alkaline/silane treatments. The biocomposite samples loaded at 20 wt% were prepared by melt compounding. Scanning Electron Microscopy (SEM) showed a better fiber-matrix interaction between Diss fiber and matrix after surface fiber treatment. Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD) results indicated an increase in crystallinity index of the biocomposites. In addition, the incorporation of Diss fibers treated with alkali-silane resulted in an improvement in Heat Deflection Temperature (HDT) and shore D hardness from 141.1 °C and 75.1–145.7°C and 86.2, respectively, in comparison with the neat matrix. This also agreed with the flexural properties results, which showed a significant increase in flexural modulus by almost 30 % compared to the neat PHBV. The same trend was observed for water absorption. Overall, combined alkali-silane treatment was found to be most efficient surface treatment method to develop strong interfacial adhesion between PHBV and Diss fiber, increasing the scope of application in manufacturing of light weight green composites.

Facile chemical surface modification of boron nitride platelets and improved thermal and mechanical properties of their polymer compounds for 2.5D/3D packaging applications

Thermally conductive yet electrically insulative epoxy composites are sought after as encapsulation materials to tackle the heat dissipation challenges in modern electronics. In this work, we developed a novel one-step and facile solvothermal reflux method using a high-boiling-point solvent to surface-modify hexagonal boron nitride (h-BN) with glycine. By refluxing glycine at high temperature, amino functional groups are grafted onto the BN surface, which can enhance the affinity of fillers for epoxy and reduce the interfacial thermal resistance of the filler/epoxy composites. We investigated the mechanism of glycine-grafted layer formation, optimizing reactant mass ratios for enhanced interfacial thermal transport. The resulting BN@G11/epoxy composites exhibit a remarkable thermal conductivity of 1.04 W/mK at 30 wt% modified-BN loading, representing a 477.8 % increase over neat epoxy and 57.5 % higher than h-BN/epoxy composites at equivalent BN filler loading. Additionally, these composites demonstrate improved thermomechanical properties, confirming the strengthened BN/epoxy interface bonding using modified BN fillers. Compared to other surface treatment methods, this solvothermal reflux approach stands out for its scalability and cost-effectiveness. This scalable and eco-friendly innovation presents a competitive strategy for designing polymer-based composites for thermal management, catering to the demands of future 2.5D/3D semiconductor packaging.

Effects of plasma surface treatment on the bond strength of zirconia with an adhesive resin luting agent.

The purpose of this study was to evaluate the effect of the atmospheric pressure plasma treatment as a surface treatment method on the contact angle and shear bond strength (SBS) of zirconia ceramics and the failure mode between the self-adhesive resin luting agent and zirconia. The zirconia specimens were divided into eight groups based on the surface treatment method: alumina blasting, air plasma, argon plasma (AP), Katana cleaner, ozonated water, ozonated water+AP, Katana cleaner+AP, and tap water+AP. The contact angles, SBS, and fracture modes were tested. AP treatment significantly reduced the contact angle (p<0.0001). The combination of AP and other cleaning methods showed a higher bond strength and more mixed fractures. Our findings indicate that using atmospheric pressure plasma with argon gas, combined with other cleaning methods, results in a stronger bond than when using alumina blasting alone.

The Research Progress of Magnesium Alloy Building Formwork.

Building formwork is a kind of temporary supporting structure consumable material used in the construction field. In recent years, building formwork has gradually developed to become lighter, more environmentally friendly, and have higher performance. This sets higher requirements for the materials used to make building formwork. There is an urgent need to find a lighter and more durable material for building formwork. Magnesium alloys possess the advantages of low density, high alkali resistance, and high strength. As a building formwork material, it can reduce the weight of formwork and improve its durability. Therefore, a magnesium alloy is considered a material with high potential for building formwork. Currently, magnesium alloy building formwork has attracted the attention of many companies and research and development institutions, with preliminary research applications and good feedback on usage effects. It is highly possible to obtain the opportunity to put it into market application. However, to be applied on a large scale, there are still some important problems that need to be solved. These problems fall into three main areas, including the relatively low processing efficiency of magnesium alloy materials, the unstable price of magnesium alloys, and the fact that the formwork is easily corroded during storage. Firstly, at present, the main processing methods for magnesium alloy building formwork are casting and extrusion, and the production efficiency of both methods needs to be improved. Secondly, high-performance magnesium alloy materials are usually more expensive, which is not conducive to the large-scale application of the formwork. The price of magnesium alloys has fluctuated greatly in recent years, which increases the difficulty of promoting magnesium alloy building formwork. Thirdly, in the atmosphere, the oxide film on the surface of the magnesium alloy cannot play an effective role in corrosion resistance. So, surface treatment is necessary for magnesium alloy building formwork. Among the various surface treatment methods for magnesium alloys, the chemical conversion method has the advantages of being easy to operate, cost-effective, and having good corrosion resistance. It may be a very suitable protective method for large-scale applications of magnesium alloy building formwork and possesses excellent potential for application. The future of magnesium alloy building formwork will focus on new low-cost materials, high-efficiency processing technology, and low-cost green anti-corrosion technology. With in-depth research and the maturation of technology, magnesium alloy formwork is expected to play a more important role in the construction industry.

Study on micro-arc oxidation coating of copper pretreated at high temperature

Micro-arc oxidation (MAO), also known as plasma electrolytic oxidation (PEO), is a surface treatment technology widely used in valve metals. As a widely used non-valve metal, copper is generally not easy to prepare MAO coating on its surface. In this paper, from the principle of MAO, the black coating was successfully prepared on the surface of pure copper by using high temperature pretreatment method and MAO technology, and the surface morphology and composition of the coating are characterised in detail. Friction experiments show that the MAO coatings formed by copper after high-temperature pretreatment at 300 °C have better wear resistance. The water contact angle test and electrochemical experiments show that the 300 °C sample has a higher water contact angle and excellent corrosion resistance. This study expands the surface treatment method of copper and provides a new idea for MAO technology in the surface treatment of other non-valve metals.

Influence of different methods of surface treatment on corrosion resistance of low-alloy steel

The influence of mechanical methods of surface treatment (polish and polish with the next strengthening by high-frequency mechanical pinning, HFMP) on the corrosion resistance of low-alloy steel 15HSND were presented. The deficiencies of surface strengthening by HFMP with one impact peen were analyzed, and an instrument in which shock elements are situated in a few rows was suggested. Speed of HFMP for the surfaces 35 sm2/min was recommended. The differences in structure and microhardness of near-surface layers of 15HSND steel with polished surface and the polished surface with next strengthening by HFMP were established after investigations in the salt frog chamber and moisture chamber during 1200 hours. Application of HFMP technology increases of corrosion resistance of steel: corrosion rate after neutral salt fog decreased from 2,543 mm/year on the polished surface to 2,096 mm/year after HFMP treatment, and after increased humidity and temperature, from 0,104 mm/year to 0,080 mm/year.

An Approach to Improve Specimen Processing for the Flexural Strength Testing of Zirconia.

Measuring the flexural strength of restorative materials such as zirconia is crucial for providing proper indications for clinical applications and predicting performance. Great variations in specimen preparation for flexural strength measurements exist among laboratories. The aim was to evaluate how the processing method, surface treatment, and test method of the specimens affect the flexural strength of zirconia. Zirconia specimens (VITA YZ HT) (n = 270) were processed using CAD/CAM or were conventionally milled with three different surface treatments (machined, ground, polished) and were measured with three-point bending (non-chamfered/chamfered) or biaxial flexural strength test. Weibull statistics were conducted. The mean flexural strength values ranged from 612 MPa (conventional, machined, three-point bending non-chamfered) to 1143 MPa (CAD/CAM, polished, biaxial flexural strength). The highest reliability is achieved when specimens are prepared using thoroughly controllable processing with CAD/CAM and subsequently polished. Higher strength values are achieved with the biaxial flexural strength test method because the stress concentration in relation to the effective volume is smaller. Polishing reduces surface microcracks and therefore increases the strength values.

Technical cleanliness of additively manufactured Inconel 718: a comparative study of surface treatment methods

PurposeMetal laser-powder-bed-fusion using laser-beam parts are particularly susceptible to contamination due to particles attached to the surface. This may compromise so-called technical cleanliness (e.g. in NASA RPTSTD-8070, ASTM G93, ISO 14952 or ISO 16232), which is important for many 3D-printed components, such as implants or liquid rocket engines. The purpose of the presented comparative study is to show how cleanliness is improved by design and different surface treatment methods.Design/methodology/approachConvex and concave test parts were designed, built and surface-treated by combinations of media blasting, electroless nickel plating and electrochemical polishing. After cleaning and analysing the technical cleanliness according to ASTM and ISO standards, effects on particle contamination, appearance, mass and dimensional accuracy are presented.FindingsContamination reduction factors are introduced for different particle sizes and surface treatment methods. Surface treatments were more effective for concave design features, however, the initial and resulting absolute particle contamination was higher. Results further indicate that there are trade-offs between cleanliness and other objectives in design. Design guidelines are introduced to solve conflicts in design when requirements for cleanliness exist.Originality/valueThis paper recommends designing parts and corresponding process chains for manufacturing simultaneously. Incorporating post-processing characteristics into the design phase is both feasible and essential. In the experimental study, electroless nickel plating in combination with prior glass bead blasting resulted in the lowest total remaining particle contamination. This process applied for cleanliness is a novelty, as well as a comparison between the different surface treatment methods.

ДИНАМИКА АКТИВНОСТИ ФЕРМЕНТОВ УГЛЕРОДНОГО ЦИКЛА В УСЛОВИЯХ ПЕРЕХОДА НА МИНИМАЛЬНЫЕ ТЕХНОЛОГИИ ОБРАБОТКИ

The purpose of research is to study the dynamics of the activity of enzymes in the carbon cycle of agrochernozems and its effect on the transformation of easily mineralizable organic compounds when using waste and surface treatment methods. Field observations were carried out on the basis of the production experience of OOO OPH Dary Malinovki in the Sukhobuzimo District in the Krasnoyarsk forest-steppe (56°10′ N and 91°47′ E). The impact of dump and minimal processing technologies on the seaso¬nal dynamics of the activity of carbon cycle enzymes in the layers of agrochernozem is considered. The field experiment scheme is represented by the following options: moldboard plowing (standard), minimal tillage (surface disking), flat-cut tillage (cultivation). The level of polyphenol oxidase activity in the soil of the experimental variants was estimated to be weak. The intraseasonal dynamics of the studied enzymes was significant and correlated with the transformation of the humus accumulation coefficient. On non-dumping backgrounds, the variability of polyphenol oxidase was less variable. The minimum va¬lues of the humus accumulation coefficient were found at the initial stage of introducing the technologies under study during the fallow period of agrochernozems, as well as during the barley growing season. The maximum is in the soil under spring wheat crops. The use of flat-cut cultivators led to a strong relationship between the activity of polyphenol oxidase and the coefficient of humus accumulation. In the soil of all variants, an inverse relationship was observed between peroxidase activity and the coefficient of humus accumulation. The participation of peroxidase in the biochemical processes of mineralization was carried out mainly under the conditions of dump processing of agrochernozems. The activity of oxidoreductase enzymes indicated favorable conditions for the humification of organic compounds and the accumulation of newly formed humic substances in the soil when spring wheat was placed in fallow under conditions of using no-moldboard technologies.

Impact of surface preparation method on the fracture toughness of adhesive joints subjected to diverse loading modes

While research has explored surface treatment effects on fracture energies in pure modes (I or II), there is a lack of research under mixed-mode loading. The aim of this paper is to investigate the influence of surface treatment approaches on the fracture behaviour and fracture energy of adhesive joints at different loading modes. To achieve this, double cantilever beam (DCB) adhesive joints were manufactured considering two different surface treatment methods namely grit blasting and mechanical bristle blasting. The joints were subjected to five different mode mixities. Fracture energy for each tested condition was calculated based on a compliance-based approach. The fracture energies in mode I reached an increase of 55 % when grit blasting surface treatment was applied, while for mode II the fracture energy reached a value three times higher for mechanical bristle blasting surface treatment, both energies from the mixed mode tests. The failure mechanisms were also evaluated for joints with different surface treatments as a function of loading mode. In all tested conditions, a cohesive failure mode was observed; however, the results underscore the substantial influence of the surface treatment method on the fracture energy of adhesive joints. This is attributed to the distinct failure mechanisms observed under varying surface treatment conditions.

Effect of Different Surface Treatments as Methods of Improving the Mechanical Properties after Repairs of PMMA for Dentures.

Denture fractures are a common problem in dental practice, and their repair is considered a first option to restore their functional properties. However, the inter-material resistance may become compromised. Typically, the bond between these materials weakens. Therefore, various surface treatment methods may be considered to enhance their mechanical properties. Poly(methyl methacrylate) (PMMA) heat-polymerized resin (HPR) was used as the repaired material, cold-polymerized material (CPR) for the repairs, and different variants of alumina abrasive blasting (AB), methyl methacrylate (M), ethyl acetate (EA), methylene chloride (CH), and isopropyl alcohol (IA) treatments were applied. Finally, combined surface treatments were chosen and analyzed. Surface morphologies after treatments were observed by scanning electron microscopy and the flexural, shear, and impact strengths were tested. AB and chemical treatment with CH, M, and EA was used to improve all mechanical properties, and further improvement of the properties could be achieved by combining both types of treatments. Varied changes in surface morphologies were observed. Treatment with IA yielded less favorable results due to the low impact strength. The best results were achieved for the combination of AB and CH, but during the application of CH it was necessary to strictly control the exposure time.

Study on Bonding Characteristics of Aluminum Alloy Treated by Plasma Electrolytic Oxidation Process and Polymer Resin Bonded by Direct Injection Molding

Aluminum alloy and polymer resin hybrid bonding technology is essential for lightweight mobile phone frames and automotive components. Recently, there has been extensive research on a method of bonding metals and polymer resins by treating the metal surface and then direct injection molding. However, this method requires separate surface treatment of the aluminum alloy after bonding to enhance its corrosion resistance. This paper studies the use of Plasma Electrolytic Oxidation, one of the surface treatment methods for aluminum, to achieve the bonding of aluminum and polymer resin in a single surface treatment step while ensuring high corrosion resistance. We conducted research to investigate optimal conditions by adjusting the process variables of Plasma Electrolytic Oxidation, in order to achieve integration with the polymer resin and measure the bonding strength and corrosion resistance. The surface characteristics of each Plasma Electrolytic Oxidation condition were analyzed using scanning electron microscopy and atomic force microscope equipment, while the bonding strength was measured using universal testing machine equipment. The corrosion characteristics were evaluated by measuring the corrosion resistance in a saltwater solution.

Simulation of voltage characteristics of vapor-gas shell during electrolyte-plasma treatment

Electrolytic plasma processing (EPT) is a method of surface treatment of materials based on the use of plasma and an electrolytic solution. This abstract discusses the principle of action, main applications and potential benefits of EPТ. The EPТ technique involves immersing the object being treated in an electrolytic solution, after which an electric current is applied, causing decomposition of the solution and the formation of a plasma cloud at the surface of the material being processed. Exposure to plasma and chemically active components of the solution makes it possible to modify the surface of the material, improving its properties, such as adhesion, strength and corrosion resistance. EPТ is widely used in a variety of industries, including metalworking, electronics, medical equipment and food processing. The advantages of the method include high efficiency, the ability to process complex shapes and materials, as well as environmental safety due to the absence of the use of chemically aggressive substances. Electrolytic plasma processing is a promising direction in the field of surface modification of materials with a wide range of potential applications. In this paper, theoretical studies of vapor-gas shell formation in the near-surface region of structural steels in the cathodic heating mode of electrolyte-plasma treatment were considered. The technology of electrolyte-plasma hardening, providing the required mechanical properties of products, which are often subjected to wear, temperature and force effects, was investigated. Based on the results of theoretical studies, mathematical calculations of voltage, current density, and dependence graphs were made to obtain a model of vapor-gas shell formation in the process of cathodic heating. Modeling of calculations of vapor-gas shell formation in the process of cathodic heating was carried out with the help of Maple program.

THE INFLUENCE OF ABUTMENT SURFACE TREATMENT ON PULL-OFF BOND STRENGTH BETWEEN (5)YTTRIA STABILIZED ZIRCONIA CROWN AND TITANIUM IMPLANT ABUTMENT

ABSTRACT Aim: The objective of this research was to evaluate the effect of mechanical method and energetic method of surface treatments for Ti-abutment base (Ti-Base, Dentium/Korea) on the pull-off bond strength with (5)Y-TZP crown. Materials and Methods: : Forty titanium implant abutments were used in this study and randomly assigned to four groups (n = 10 for each group) according surface treatment methods of titanium abutment: group (1) act as control without surface treatment for Ti-abutment, group (2) bur surface treatment of Ti-abutment, group (3) sandblast (50-µm aluminum oxide) surface treatment for Ti-abutment, group (4) plasma surface treatment for Ti-abutment. Then, forty implant analogs were placed in the center of acrylic mold. After that abutment was tightened on the each analog with (35 N/cm) torque . Forty (5)Y-TZP crowns fabricated by CAD/CAM system that had special design with occlusal O-hole cemented to all abutments using Allcem dual-cure resin cement. All specimens were then subjected to thermos-cycling with (5000) cycles. With a universal testing machine record pull-off bond strength for all samples, Collected data were analyzed using a one-way analysis of variance at a significance level of (p &lt; 0.01) . Results:, The bur treated abutment (group 2) group showed the highest bond strength values, followed by sandblast treated abutment (group 3) and plasma treated abutment (group 4). Control group was the lowest value of tensile strength. Conclusion: Surface treatments of Ti-abutment had observed effect on pull-off (tensile bond strength) between Ti-abutment and (5)Y-TZP crown Bur and sandblast cause roughness of surface and increase bond strength , plasma cause reactive surface for increasing tensile bond strength.