Increasing the adhesion forces of hydroxyapatite B, F, and Zr-reinforced coatings

Effect of layered manufacturing techniques, alloy powders, and layer thickness on metal-ceramic bond strength

PurposeAISI 4140 is a versatile, low alloy steel often used in various applications in mechanical systems and manufacturing processes. To mention a few in processes such as friction stir welding tooling and in engine components, temperatures above 700°C coupled with wear. Despite its versatility, it is still susceptible to wear and corrosion. A common method to address this shortcoming is physical vapor deposition (PVD) coating. This study aims to experimentally investigate the wear performance of AISI 4140 PVD coated with titanium nitride (TiN) and titanium aluminum nitride (TiAlN) at room and elevated temperatures.Design/methodology/approachTwo sets of three samples were prepared. Where one sample was uncoated AISI 4140, TiN and TiAlN PVD coated, one set was tested at room temperature and the other set at 780°C for comparison purposes. The average coating thicknesses were measured, and the adhesion properties were assessed using a scratch test. Their tribological wear scars were further characterized using scanning electron microscope (SEM) energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), Raman and confocal microscopy, and the results were furnished in the paper.FindingsWith the scratch test, the first critical load (Lc) on the TiAlN coating was 15% higher than that of the TiN coating. At room temperature, TiN had the highest coefficient at 0.61, while TiAlN was 0.39. After 1,500 s, samples showed run-in and stability. At elevated temperatures, TiAlN started with the highest friction but stabilized later than TiN and uncoated samples, which stabilized after 200 s due to titanium oxide formation. This was due to the formation of an oxidation layer caused by the thermal environment. Hence, the opposite is observed at room temperature. The findings were supported by the Raman, XRD, SEM EDS and areal topography analysis.Originality/valueThe results presented in the study are valuable to design engineers and researchers anticipating wear in high temperature applications. Therefore, with these results, reasonable, informed decisions can be made about specific design requirements.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0354/

Bonding behavior during cold roll-cladding of tri-layered Al/brass/Al composite

This paper presents an experimental investigation of the bond strength between carbon fiber reinforced polymer (CFRP) and steel substrate by utilizing the pull-off test and scanning electron microscope (SEM) analysis. A series of pull-off experiments was conducted by using three types of CFRP (CFRP sheets and CFRP laminates with/without woven mesh) and two types of epoxy adhesive (ductile and brittle epoxy adhesive) with/without carbon nanotube (CNT) modification. Pull-off samples with CFRP laminates possess higher (about double) bond strength than that of samples with CFRP sheets, due to the good saturation of fibers in the laminates. The steel-CFRP bond with ductile epoxy adhesive (Araldite 2011) is found to have about 16% higher bond strength when compared to that of brittle epoxy (MBrace Saturant), even though the tensile strength of Araldite 2011 is about 40% less than that of MBrace Saturant. Also, it is shown that modified epoxy with CNTs is more efficient than neat epoxy for bonding CFRP to steel at a moderately elevated temperature, and increasing the bond strength about twofold.

To evaluate the effect of different resin cements and dentin surface treatment methods on shear bond strength between glass ceramic and human dentin. Freshly extracted non-carious human premolars were collected to prepare flat mesial and distal dentin surface with diamond bur. Besides, ceramic discs (3 mm in diameter, 3 mm in height) were fabricated with IPS e. max Press ingots. All samples were randomly divided into five groups, sixteen specimens each. Ceramic discs were cemented on dentin surface using one of the five resin cements [Group A (Variolink II), Group B (Multilink Automix), Group C (Multilink Sprint), Group D (Rely X Unicem) and Group E (BisCem)] respectively. Half of the specimens were stored in water 37 degrees C for 24 h and the other half were additionally thermocycled for 5000 times (5 degrees C/55 degrees C) before shear bond strength test. Dentin bonding surface and transverse plane were examined with a scanning electronic microscope. Group A showed the highest bond strength before thermocycling [(22.3 +/- 3.9) MPa], and the bond strength of Group B [(18.1 +/- 3.5) MPa] was lower than that of Group A (P < 0.05). Group E [(11.7 +/- 4.2) MPa], Group C [(11.3 +/- 3.6) MPa] and Group D [(14.1 +/- 2.3) MPa] had the lowest bond strength. After thermocycling, Group A still showed the highest bond strength [(17.8 +/- 2.3) MPa]. The bond strength of Group B [(14.4 +/- 3.5) MPa] and Group D [(13.2 +/- 2.5) MPa] were lower than that of Group A. Group E [(8.9 +/- 3.2) MPa] and Group C [(7.0 +/- 2.4) MPa] showed the lowest bond strength. The bond strength of all groups decreased notably after thermocycling except Group E and Group D. The resin cement based on etch-rinsing bonding system has higher bond strength to dentin than those based on self-etch bonding system and self-adhesive resin cements.

The combination of hydrofluoric (HF) acid and silane can provide sufficient bond strength for porcelain crowns. However, it requires careful isolation to prevent hurting soft tissue. Phosphoric (H3PO4) acid is safe for porcelain surface treatment, but the bond strength of its combination with silane agents as an orthodontic adhesive to porcelain has seldom been reported. This study evaluates the bond strength obtained using various acid-silane agents and porcelain fracture after debonding. One metal bracket, one orthodontic adhesive (Enlight), two etching agents (37 % H3PO4 and 9 % HF), three silane agents (Ormco Porcelain Primer, Ultradent Silane, and Jeneric/Pentron Silane), and 50 porcelain crowns were tested. The shear bond strengths were determined and the porcelain surfaces were observed using scanning electron microscopy after debonding. One-way analysis of variance (ANOVA) was used to analyze the shear bond strengths and the inter-group comparison was conducted using the Tukey test. Cross-matching of two types of acid and two types of silane (Ultradent and Jeneric/Pentron Silane) was compared using two-way ANOVA. Fisher’s exact test was used to analyze the porcelain fracture index (PFI) scores. The Porcelain Primer group had the lowest bond strengths and the H3PO4-Jeneric/Pentron silane group had the highest bond strengths (p < 0.0005). Cross-matching of acid and silane showed that acid had a statistically significant effect on bond strength. There was a statistically significant difference in adhesive remnant index scores between Porcelain Primer and the other groups (p < 0.005). There were no statistically significant differences in the PFI scores among all silane groups. The H3PO4-Jeneric/Pentron silane group had the highest bond strength among all acid-silane groups and its risk of porcelain fracture was not higher than that of other acid-silane groups.

The aim of this study was to evaluate the effects of proanthocyanidin (PA) and chlorhexidine (CHX) on the bond strength (BS), failure pattern, and resin-dentin interface morphology of the endodontic sealers EndoREZ and AH Plus after 24 h and 6 months of water storage. A total of 120 prepared bovine roots were divided into six groups: AH Plus, CHX+AH Plus, PA+AH Plus, EndoREZ, CHX+EndoREZ, and PA+EndoREZ. Dentin was treated for 1 or 5 min with 2% CHX or 15% PA, respectively. Roots were filled and stored in water for 24 h or 6 months (n = 10). Root slices were subjected to push-out test and scanning electron microscopy (SEM). Data were compared using two-way ANOVA and student's t-test (α = 5%). BS decreased over time for AH Plus and untreated EndoREZ (p < 0.05). At 24 h, AH Plus had higher BS than EndoREZ (p < 0.001), with no differences among treatments for both sealers (p > 0.05). At 6 months, EndoREZ had higher BS values for CHX and PA than control (p < 0.05). AH Plus had higher BS than EndoREZ (p < 0.001), while with CHX or PA, similar BS was observed in both sealers (p > 0.05). Cohesive and mixed failures were observed in all groups. SEM revealed sealer tags in the root dentin. In conclusion, BS decreased with time and AH Plus had higher BS than EndoREZ in untreated dentin; however, CHX or PA enhanced long-term BS of EndoREZ. Overall, dentin treatment affected failure pattern and resin-dentin interface morphology, particularly for EndoREZ.

Characterization of carbon and zirconia films deposited on polycarbonate for scratch-proof coating applications

Effect of calcination temperature on the photocatalytic activity and adhesion of TiO 2 films prepared by the P-25 powder-modified sol–gel method

Tribological characteristics of Ti-Si-N films deposited by unbalanced DC magnetron sputtering

Relationship between thin-film bond strength as measured by a scratch test, and indentation hardness for bonding agents

Comparison of bond strengths of denture base resins to nickel-chromium-beryllium removable partial denture alloy

The aim of this current study was to compare and evaluate the reversal efficacy of Qmix and chitosan-based irrigation materials quantitatively through the assessment of the push-out bond strength of bioceramic sealer employing universal testing machine and to qualitatively analyze the sealer/dentin interface by scanning electron microscope (SEM) in the teeth subjected to fractioned radiation. Ninety single-rooted straight human maxillary central incisors were randomly divided into six groups (n = 15) where in three groups comprise Chitosan, Qmix, and EDTA/sodium hypochlorite which were not exposed to irradiation while other three groups were challenged with irradiation protocols. Root canals were prepared with ProTaper universal system and all the samples were irrigated according to the final irrigation protocols and obturated with bioceramic sealers. Dentin slices were prepared with 1 mm thickness from each root third for the estimation of bond strength of sealers to dentin. Qualitative assessment of the sealer-dentin interface was done by scanning electron microscopy. Bond strength data were scrutinized by independent t-test and failure modes using the Chi-square test. Significantly lower bond strength (p <0.05) was recorded after irradiation compared with nonirradiated group. To quantify the results irrigation protocols, Qmix had highest bond strength followed by chitosan and EDTA/sodium hypochlorite group irrespective of irradiation status. Bond strength values reduced after irradiation in all root thirds irrespective of the irrigation materials. Scanning electron microscope images revealed traces of repair process for Qmix-based irrigation materials than the chitosan-based materials for both irradiated and nonirradiated specimens. All the irrigation materials employed in this study had good bond strength. The specimen irrigated with Qmix had comparatively higher bond strength than the chitosan-based materials. The teeth subjected to irradiation challenge were associated with a decrease in the push-out bond strength of sealers to intraradicular dentin with formation of more gaps and fewer tags at the sealer/dentin interface. Selection of ideal irrigation protocols still remains a challenge for the clinical practitioners, and this study explored the utilization of novel materials used for irrigation, especially in the teeth subjected to radiation.

Introduction: The study aimed to assess the impact of fractionated radiation on push-out bond strength of sealer to dentin interface and on marginal adaptation of the sealer (Adseal, MTA Fillapex, and EndoSequence BC sealer) to irradiated dentin.Materials and Methods: Ninety maxillary central incisors were randomly divided into two groups: with irradiation (n = 45) and without (n = 45). All the samples to be radiated were exposed to fractionated dosage (60 Gy) through Co-60 gamma (1.17 and 1.33 Mev) photons. Specimens were prepared and subdivided into three subgroups (n = 15 each) according to assigned sealer Adseal, MTA Fillapex, and EndoSequence BC sealer. Later, the samples were sectioned into a 1 mm thick segment at each root third for bond strength and scanning electron microscope (SEM) analysis. SEM micrographs were analyzed with an ORION version 6 image analyzer. The percentage of failure mode after debonding was evaluated with a stereomicroscope. Bond strength data were analyzed using two-way analysis of variance and the Tukey's post hoc test.Results: Bond strength was significantly (P < 0.0001) decreased after radiotherapy (0.76 ± 0.12 Mpa) versus without radiation (0.93 ± 0.18 Mpa). Furthermore, when the pooled average of sealers was compared, significantly highest bond strength was perceived in Adseal (0.98 ± 0.18 Mpa) followed by EndoSequence BC (0.84 ± 0.13 Mpa). Coronal sections showed significantly (P < 0.0001) higher bond strength (0.99 ± 0.16 Mpa) compared to the middle (0.81 ± 0.14 MPa) and apical third (0.74 ± 0.12 Mpa). Qualitative SEM revealed a higher interfacial gap between sealer and irradiated radicular dentin. The percentage of mean change was recorded significantly high in MTA Fillapex (52%), then in EndoSequence BC (31%), and least was in Adseal (17%).Conclusions: Irradiated teeth resulted in consequential decreased adhesiveness and bond strength of dentin to root canal filling material. In addition, the highest bond strength was noticed in Adseal.

Enhancement of adhesion strength and in-vivo evaluation of electrodeposited calcium phosphate/chitosan biocoatings on titanium substrate