Wear resistance of TC4 by deformation accelerated plasma nitriding at 400 °C

An integrated low temperature nitriding process for TC4（Ti6Al4V） has been developed and the effect on wear resistance has been investigated. Through the process of solid solution strengthening—cold deformation—nitriding at 400℃, the TC4 alloy is nitrided on surface and dispersion strengthened in bulk at the same time. The white nitriding layer is formed after some time of nitriding. The nitriding speed increases with the deformation degree. The construction was investigated by XRD and the nitride is Ti3N（2-X）. The wear test was carried out and results exhibit that the nitrided samples have better wear resistance.

Effects of Substrate Pretreatment Conditions on Quality of GaN Epilayer

The pure cubic GaN(c-GaN) has been grown on (001)GaAs substrates by ECR-PAMOCVD technique at low temperature using TMGa and high pure N2 as Ga and N sources, respectively. The effects of substrate pretreatment conditions on quality of cubic GaN epilayer are investigated by the measurements of TEM and XRD.It is found that hydrogen plasma cleaning, nitridation and buffer layer growth are very important for quality of cubic GaN epilayer.

High Density Plasma Nitriding of Al-Cu Alloys for Automotive Parts

Duralumin alloys have been utilized as structural components and parts for aircrafts, train-cars and so forth. Their high specific strength was attractive to those applications; however, their little corrosion resistance and low wear endurance became a fatal demerit in practical applications. In order to overcome these issues of high strength aluminum alloys, high density plasma nitriding is proposed as an effective surface treatment for duralumin. This process has a capability to control the RF- and DC-plasmas independently for nitriding. This enables us to temporally control and describe the plasma state by in-situ plasma diagnosis. This plasma diagnosis was instrumented to search for optimum processing condition to plasma nitriding the duralumin alloys of type A2011. Both type A2011 aluminum alloy plates and pipes were employed to describe the inner nitriding behavior for hardening the duralumin alloys by the present plasma nitriding.

Surface modification of Ti-6Al-4V alloy by cathode assiting discharge setup and conventional plasma nitriding methods

In order to improve the wear resistance of titanium alloys,the potential of the plasma nitriding process with a cathode assiting discharge setup was examined.Ti6Al4V alloy was nitrided by the cathode assiting discharge nitriding(CAN) and conventional DC plasma nitriding(CPN) methods,respectively.The micro-topography,phase composition and cross-sectional microhardness distribution of two nitriding layers were studied comparatively.The sliding wear resistance of the nitriding layers was examined by a ball-on-disk test against Si3N4 balls.The results indicated that the surface roughness Ra of the CAN layer was about 1 order less than that of the CPN layer.In addition,the CAN surfaces possessed significantly greater wear resistance than the CPN layer at higher loads,and increased the wear resistance of Ti6Al4V alloy by about 2 orders due to the higher loading bearing ability,higher rate of TiN phase,greater surface microhardness and bigger microhardness improving depth.This is because the double glow discharge effect in CAN strengthened the density of the active nitrogen atoms and the nitriding efficiency.Moreover,the ion bombardment effect on the surface of the nitriding titanium alloy was reduced obviously.