DSI Method Research Articles

Microstructure and Properties of Electroless Ni-P/Si3N4 Nanocomposite Coatings Deposited on the AW-7075 Aluminum Alloy.

The article presents the results of mechanical and tribological tests of Ni-P/Si3N4 nanocomposite coatings deposited on the AW-7075 aluminum alloy using the chemical reduction method. The influence of the chemical composition on the Vickers microhardness determined by the DSI method was examined. The nanocomposite layers were made of Si3N4 silicon nitride in a polydisperse powder with a particle size ranging from 20 to 25 nm. The influence of the content of the dispersion layer material on the adhesion to the substrate was analyzed. The abrasive wear was tested and determined in the reciprocating motion using the “ball-on-flat” method. The surface topography was examined by the contact method with the use of a profilometer. Based on the obtained test results, it was found that the Ni-P/Si3N4 layers produced in the bath with the Si3N4 nanoparticle content in the amount of 2 g/dm3 are more resistant to wear and show greater adhesion than the Ni-P/Si3N4 layers deposited in the bath with 5 g/dm3 of the dispersion phase. NiP/Si3N4 layers provide protection against abrasive wear under various loads and environmental conditions.

The Influence of Process Parameters of Injection on Nano-mechanical Properties of Polypropylene

Injection of polymers is one of the most widely used technology in the production of plastic parts. During injection moulding it is important to analyse the individual factors of the injection process so that the optimal injection parameters can be set from these established process conditions. When injecting, it is important to achieve the optimal production process to reach optimal production costs, increasing the quality of the product and eliminating possible defects in the products. The presented work deals with the investigation of the influences of the process parameters of the injection process (holding pressure and mould temperature) on resulting nano-mechanical properties. To measure nano-mechanical properties by the DSI method, a polypropylene sample was chosen. Measurements were performed on the Nano-Combi-Tester. From the results of this study it is clear that optimal nano-mechanical properties are required to optimize the process parameters of the whole injection moulding process.

Examination of selected properties of BNi-1a and BNi-2 coatings by DSI method

This paper describes examination of selected mechanical properties of the Ni-Cr-B-Si coatings using the DSI method (Depth Sensing Indentation). The research was carried out on coatings obtained in a vacuum furnace-melting process of two alloys: BNi-1a and BNi-2. The alloys in paste form had a different content of Ni, Cr and Fe. Change in the content of these elements affects the size and density of the distribution of chromium borides. In the BNi-1a coating, the precipitations are fine-grained and densely distributed in the nickel matrix. While, in the BNi-2 coating they are larger and occur in dendritic agglomerations, on the surface they are in the form of plaques. The DSI tests showed that the BNi-1a coating has a higher hardness (by 22.4–25.0%), stiffness (by 39.4%) and creep resistance (by 7.9%) than the BNi-2 coating.

The influence of thickness of Ni-P layers produced on AW-7075 aluminum alloy on their adhesion and mechanical properties

The article presents the results of mechanical tests of Ni-P layers deposited by the chemical reduction method on the AW-7075 aluminum alloy. The effect of layer thickness on hardness and microhardness of Vickers, which was determined by the DSI method, and their adhesion to the substrate by scratch method were investigated. The morphology was obtained using light microscopy and the topography of the examined layers using a contact profilometer. Different thicknesses were used to determine their effect on adhesion of the leyers to AW-7075 alloy. The results allowed to state that Ni-P layers of higher thickness are characterized by higher hardness and Young's modulus values than thinner Ni-P layers, and also show better adhesion to the AW-7075 alloy.

Nano-indentation test of electron beam irradiated polyamide 11

This article deals with the influence of electron beam radiation on nano-mechanical properties and the structure of polyamide 11. Crosslinking of polymers is a process, during which macromolecular chains start to connect to each other and the spatial network creates in the structure. During the action of the ionizing radiation two actions can occur: crosslinking and scission of macromolecules – degradation. Both these processes run parallel. Using the crosslinking technology the standard and construction polymer can obtain the more “expensive” high-tech polymeric materials properties and thus replace these materials in many applications. Tested material was irradiated by different doses of beta radiation (33, 66 and 99 kGy). The nano-mechanical properties were measured using DSI method, which fluently records the change of the indentation in time. From this dependence it is possible to determine nano-mechanical properties such as indentation hardness, indentation modulus etc. During results consideration it is obvious that irradiation acts on each polymer differently, but always when the optimal dose was found, nano-mechanical properties increased up to 34 %. The changes of nano-mechanical properties were confirmed by structural measurement when the change of hardness and modulus corresponded to gel content.

Micro-Hardness Test of Cross-Linking LLDPE

The presented article deals with the research of micro-mechanical properties in the surface layer of modified linear polyethylene (LLDPE). These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation (0, 66, 132 and 198 kGy ). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the LLDPE tested. The highest values of micro-mechanical properties were reached at radiation dose of 132 kGy, when the micro-hardness values increased by about 29%. These results indicate advantage crosslinking of the improved mechanical properties.

The influence of the cumulated deformation energy in the measurement by the DSI method on the selected mechanical properties of bone tissues.

The goal of the study was to determine the influence of DSI test conditions, i.e., loading/unloading rates, hold time, and the value of the maximum loading force on selected mechanical properties of trabecular bone tissue. The test samples were resected from a femoral head of a patient qualified for a hip replacement surgery. During the DSI tests hardness (HV, HM, HIT) and elastic modulus (EIT) of trabecular bone tissue were measured using the Micro Hardness Tester (MHT, CSEM). The analysis of the results of measurements and the calculations of total energy, i.e., elastic and inelastic (Wtotal, Welastic, Winelastic) and those of hardness and elasticity made it possible to assess the impact of the process parameters (loading velocity, force and hold time) on mechanical properties of bone structures at a microscopic level. The coefficient k dependent on the EIT/HIT ratio and on the stored energy (ΔW = Wtotal - Welastic) is a measure of the material reaction to the loading and the deformation of tissue.

The Behaviour of Cross-Linking Filled PA66 by Micro-Indentation Test

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Micro-mechanical changes in the surface layer of glass-fiber filled PA 66 modified by beta radiation were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The specimens were prepared by injection technology and subjected to radiation doses of 0, 33, 66 nad 99 kGy. The change of micro-mechanical properties is greatly manifested mainly in the surface layer of the modified polypropylene where a significant growth of micro-hardness values can be observed. Indentation modulus increased from 1.8 to 3.0 GPa (increasing about 66%) and indentation hardness increased from 87 to 157 MPa (increasing about 80%). This research paper studies the influence of the dose of irradiation on the micro-mechanical properties of semi-crystalline polyamide 66 filled by 30% glass fiber at room temperature. The study is carried out due to the ever-growing employment of this type of polymer.

The Effect of Cross-Linking on Nano-Mechanical Properties of Polyamide

Radiation crosslinking of polyamidu 6 (PA 6) is a well-recognized modification of improving basic material characteristics. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. This research paper deals with the possible utilization of irradiated PA6. The material already contained a special cross-linking agent TAIC (5 volume %), which should enable subsequent cross-linking by ionizing β – radiation (15, 30 and 45 kGy). The effect of the irradiation on mechanical behavior of the tested PA 6 was investigated. Material properties created by β – radiation are measured by nanoindentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of nanoindentation test shows increasing in nanomechanical properties of surface layer. The highest values of nanomechanical properties were reached radiation dose of 45 kGy, when the nanomechanical values increased by about 95%. These results indicate advantage cross-linking of the improved mechanical properties.

The Behaviour of Cross-Linking Filled PP to Micro-Indentation Test

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. The aim of the experiments was to study the influence of different doses of Beta radiation to the structure and micro-mechanical properties of polypropylene filled by 30% glass fiber (PP+GF). Hard surface layers of PP+GF can be formed by radiation cross-linking by β – radiation with doses of 33, 66 and 99 kGy. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the PP+GF tested. Micro-mechanical properties increased with increasing value of the dose of irradiation material (increase about 49%). The changes were examined and confirmed by X-ray diffraction.

Effect of High Doses Beta Irradiation on the Micromechanical Properties of Surface Layer of Glass-Filled Polypropylene

The presented article deals with the research of micro-mechanical properties in the surface layer of modified Polypropylene filled by 25% of glass fibers. These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. Radiation doses used were 0, 66 and 99 kGy for filled Polypropylene with the 6% cross-linking agent (triallyl isocyanurate). The change of micromechanical properties is greatly manifested mainly in the surface layer of the modified polypropylene where a significant growth of microhardness values can be observed.

Improvement of PA6 Mechanical Properties by Radiation Cross-Linking

Influence of mechanical properties of the hard surface layer of modified polyamide 6 is studied. Mechanical properties are acquired by nanohardness test with using the DSI method (Depth Sensing Indentation). Hard surface layers are created by radiation cross-linking technology. This technology allows polymer materials modification followed by the change of their end-use properties. The surface layer of polymer material is modified by ionizing β - radiation. When the polymer material is exposed to the β radiation, it is possible to observe changes of the surface layer at applied load. Radiation cross-linking usually improves strength, reduces creep, contributes to chemical resistance improvement, and in many cases improves tribological properties.

Irradiation of Polyamide Measured by Micro-Indentation Test

Cross-linking is a process in which polymer chains are associated through chemical bonds. This research paper deals with the possible utilization of irradiated polyamide. Influence of the intensity of irradiation on micro-indentation hardness was investigated. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of micro-indentation test shows increasing in micro-mechanical properties of surface layer. The highest values of micro-mechanical properties were reached radiation dose of 99 kGy, when the micro-mechanical values increased by about 18%.

Influence of Irradiation Doses on Mechanical Properties of Glass Fiber Filled PBT

The submitted paper compares mechanical properties of the hard surface layer of modified PBT filled by 35% of glass fibers. Hard surface layer was made by radiation cross-linking technology which allows polymer materials modification followed by the change of their end-use properties. The surface layer of polymer material is modified by β – radiation. When the polymer material is exposed to the β – radiation, it is possible to observe changes of the surface layer at applied load. The mechanical properties were measured by nanohardness test with using the DSI method (Depth Sensing Indentation).

Influence of Irradiation Doses on Mechanical Properties of PA6

The presented article deals with influence of mechanical properties of the hard surface layer of modified polyamide 6. The mechanical properties were acquired by nanohardness test with using the DSI method (Depth Sensing Indentation). Hard surface layer was created by radiation cross-linking technology. This technology allows polymer materials modification followed by the change of their end-use properties. The surface layer of polymer material is modified by β - radiation. When the polymer material is exposed to the β radiation, it is possible to observe changes of the surface layer at applied load.

Effect of Beta Low Irradiation Doses on the Filled PA66 Measured by Micro-Indentation Test

The presented article deals with the research of micro-mechanical properties in the surface layer of modified Polyamide 66 filled by 30% of glass fibers. These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. Radiation doses used were 0, 15, 30 and 45 kGy for filled Polyamide 66 with the 6% cross-linking agent (triallyl isocyanurate). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the polyamide 66 tested. The highest values of micro-mechanical properties were reached at radiation dose of 30 kGy, when the micro-hardness values increased by about 64%. The aim of the article is to find out the influence of the radiation on the micro-hardness of the modified glass fiber-filled Polyamide 66 (PA66).

Ionizing Radiation Effect of HDPE Measured by Nano-Hardness

This article deals with the influence of different doses of Beta radiation on nanomechanical properties of High-density polyethylene (HDPE). These nanomechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The highest values of nanomechanical properties were reached at radiation dose of 99 kGy, when the nanohardness values increased by about 23%. The purpose of the article is to consider to what extent the irradiation process influences the resulting nanomechanical properties measured by the Depth Sensing Indentation method.

Corelation of Results of Creep and Micro-Indentation Creep for PP-Copo

This article deals with the comparison of methods for measuring the creep behavior of filled polypropylene. Creep was measured by two methods, using the micro-indentation method (Depth Sensing Indentation - DSI) and the standard long-term creep test at elevated temperature. Results of this article show the feasibility of these two methods to replace each other and thus shorten the length of the testing material development with evaluation whether the test material is better or worse than the previous. Using the DSI method we can evaluated other material properties at the same time, which may be an important contributor in determining an appropriate application of the material. Mixtures of polypropylene with different kinds and levels of filling were selected for the comparison.

Micro-Hardness and Morphology of LDPE Influenced by Beta Radiation

This article deals with the influence of different doses of Beta radiation to the structure and mico-mechanical properties of Low-density polyethylene (LDPE). Hard surface layers of polymer materials, especially LDPE, can be formed by radiation cross-linking by β radiation with doses of 33, 66 and 99 kGy. Material properties created by β radiation are measured by micro-hardness test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the LDPE tested. The highest values of micro-mechanical properties were reached at radiation dose of 66 and 99 kGy, when the micro-hardness values increased by about 21%. The changes were examined and confirmed by X-ray diffraction.

Effect of Beta Irradiation on Microhardness of Polyamide 6

The polymer additional cross-linking influences the surface nano and micro layers in the way comparable to metals during the thermal and chemical-thermal treatments (e.g. surface hardening, cementation). Our research confirms the comparable properties of surface irradiated polyamide 6 (PA6) with high performance polymers. The surface layer of polymer material such as polyamide 6 is modified by β – radiation. Material properties of the surface layer created are measured by microhardness test using the DSI method (Depth Sensing Indentation). The influence of irradiation dose on mechanical properties (materials parameter) of PA6 is a subject of this research.