จำนวน Repository ( 3 )

การพัฒนาโครงสร้างเกรนต้านทานการสึกหรอของชิ้นงานความแข็งสูงพิเศษด้วยกระบวนการอบผนึก
การพัฒนาโครงสร้างเกรนต้านทานการสึกหรอของชิ้นงานความแข็งสูงพิเศษด้วยกระบวนการอบผนึก

This study developed the cemented tungsten carbide by steadily sintering at 1430 °C for one hour. The tungsten carbide structure is a long shape. Its grain size has a difference between width and length and there are high distribution of sizes and shapes. In comparison with the work piece which has the similar size of grain structure the milling duration of tungsten carbide is less even though the condition of WC-Co is the same (95% WC – 5% Co). When the sintering of 1400 °C with the identical milling duration is performed. It turned out that both grain structures of the tungsten carbide and the work piece are similar and their grain sizes are slightly different. However when the grain structures are almost the same and sphericity is increased the hardness and wear resistance will also be improved. Therefore the size of grain structure between 1.00 – 3.00 μm with the milling duration of 100 hours will provide a work piece that has a wear resistance according to international standard

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Molecular weight polyethylene composites for high wear resistance under temperature changes and lubricant to apply for use in industrial machinery parts
Molecular weight polyethylene composites for high wear resistance under temperature changes and lubricant to apply for use in industrial machinery parts

The objective of this research is a study to determine optimum forming condition of semi-finished bulk UHMWPE by using ram extruder that obtain maximum yield strength and minimum wear rate for apply to use in area of medical and mechanical application. Experimental extrusion specified forming condition consists of the temperature of 140 150 and 160 ºC and pressure of 3 5 8 and 10 MPa with the temperature exposure time of 30 minutes. After known optimum forming condition of UHMWPE powder thus forming UHMWPE filled with different kind of filler to study and determine optimum weight fraction of various types of filler that affect onto wear resistance property of UHMWPE composites. Result extruded condition at the temperature of 1 5 0 ºC under pressure of 5 MPa with exposure time of 30 minutes is an optimum extruded condition due to specimen shown a maximum yield strength ultimate tensile strength and elongation of 20.43 ± 1.21 MPa 28.33 ± 1.53 MPa and 285.60 ± 6.41 % respectively and obtain minimum wear rate of 3.02  10-9 ± 5.27  10-10 mm3/Nm. Its mechanical properties and wear resistance property higher than imported bulk UHMWPE by 23.3 % and 4.75 times respectively due to the formation of cross-linking are occurred in polymer chain and also its degree of crystallinity is high equal to 61.52%. For bulk UHMWPE IR-spectrum shown a variation peak of carbonyl group (C=O) are occurred that that it indicated the oxidation reaction at the end of polymer chain and tis degree of crystallinity is equal to 53.31% which result to decrease strength of polymer. In the case of UHMWPE filled with filler optimum weight fractions of various types of filler are as follows. 1. The filling of 0.3 wt. % Al2O3 particle size 0.05 μm shown yield strength ultimate tensile strength and elongation of 23.17 ± 3.35 MPa 34.78 ± 2.80 MPa and 229.00 ± 6.09% respectively that its mechanical properties was increased by 18.55% (increasing of ultimate tensile strength). For the wear rate is equal to 2.09  10-9 ± 3.39  10-10 mm3/Nm or its wear resistance was increased by 1.44 times in compared with initial bulk UHMWPE. 2. The filling of 0.4 wt. % Al2O3 particle size 0.3 μm shown yield strength ultimate tensile strength and elongation of 21.93 ± 0.51 MPa 25.40 ± 0.69 MPa and 267.67 ± 22.03% respectively that its mechanical properties was increased by 11.54% (increasing of ultimate tensile strength). For the wear rate is equal to 2.32  10-9 ± 4.78  10-10 mm3/Nm or its wear resistance was increased by 1.30 times in compared with initial bulk UHMWPE. ฉ 3 . The filling of 0.4 wt. % Al2O3 particle size 1 μm shown yield strength ultimate tensile strength and elongation of 23.93 ± 1.89 MPa 26.77 ± 1.20 MPa and 296.54 ± 7.51% respectively that its mechanical properties was increased by 5.83% (increasing of ultimate tensile strength). For the wear rate is equal to 2.14  10-9 ± 3.16  10-10 mm3/Nm or its wear resistance was increased by 1.41 times in compared with initial bulk UHMWPE 4 . The filling of 4 wt. % Al2O3 particle size 5 μm shown yield strength ultimate tensile strength and elongation of 22.57 ± 2.01 MPa 26.31 ± 3.11 MPa and 136.66 ± 11.67% respectively that its mechanical properties was increased by 7.68% (increasing of ultimate tensile strength). For the wear rate is equal to 2.37  10-9 ± 5.71  10-10 mm3/Nm or its wear resistance was increased by 1.27 times in compared with initial bulk UHMWPE

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การปรับปรุงสมบัติทางไทรโบโลยีของผิวอะลูมิเนียมด้วยกระบวนการอโนไดซ์เสริมนาโนไททาเนียมไดออกไซด์
การปรับปรุงสมบัติทางไทรโบโลยีของผิวอะลูมิเนียมด้วยกระบวนการอโนไดซ์เสริมนาโนไททาเนียมไดออกไซด์

Aluminium was used in many industrial applications due to good properties such as ductile high corrosion resistant and high electrical conductivity. Since wear resistance of aluminium was very poor so that it was a limitation of using this material in several conditions. In this research aluminium was improved the wear resistance properties by using anodizing process and adding some titanium dioxide particles on the surface. The effect of anodizing process duration on the wear resistence property was studied. It was found that the process duration and amount of titanium dioxide play the important role on improvement of tribological properties of aluminium.

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