Duplex Surface Treatment due to Combined Plasma Nitriding and Ceramic or Cermet Thick Coatings of Cr-Ni-N System

对304奥氏体不锈钢进行了803k离子渗氮和Cr-N或CrNi-N离子镀的双重处理。在2.5 Pa左右的纯n2或N_2- h_2混合气体中沉积Cr-N或CrNi-N的氮化膜，膜厚为3-34mum。得到如下结果：(1) Cr-N体系的相组成为CrN的单相或Cr_2N与Cr的混合相，CrNi-N体系的相组成为Cr^<**>N与Ni的混合相。Cr^<**>N是新观察到的含Ni的氮化铬，经鉴定为f.c.c结构（a=0.37 nm）。(2)膜层硬度Cr-N约为Hv 1900， CrNi-N约为Hv 1000。CrNi-N膜的沉积速度比Cr-N膜快，但表面粗糙度更大。(3)在预氮化钢表面涂覆CrN陶瓷膜，即使在重载下也表现出最佳的耐磨性。在3、10和19 μ m的CrN膜中，厚度为10 μ m的CrN膜的磨损最小，涂覆在未处理钢上的厚度大于10 μ m的CrN膜的磨损损失几乎与涂覆在预氮化钢上的CrN膜的磨损损失相近。(4)未处理钢表面涂覆的CrNi-N陶瓷膜具有良好的耐磨性，而预氮化钢表面涂覆的CrNi-N陶瓷膜的耐磨性低于未处理钢表面涂覆的CrNi-N陶瓷膜，这与CrN等普通陶瓷膜的趋势相反。

Austenitic type 304 stainless steel was duplex treated by ion-nitriding at about 803 K and subsequent ion-plating of Cr-N or CrNi-N.The nitride films of Cr-N or CrNi-N were deposited in the pure N_2 or N_2-H_2 mixed gas at about 2.5 Pa with a film thickness of 3-34mum. The following results are obtained.(1) As for the Cr-N system, the phase composition was a single phase of CrN or the mixed phases of Cr_2N and Cr. As for the CrNi-N system, it was the mixed phases of Cr^<**>N and Ni. Cr^<**>N was newly obserbed Cr nitride which may contain some Ni and identified as an f.c.c.structure (a=0.37 nm).(2) The film hardness was about Hv 1900 for Cr-N and about Hv 1000 for CrNi-N.The depositing rate of the CrNi-N film was faster than that of Cr-N,but the surface roughness was larger.(3) The ceramic flims of CrN coated onto the pre-nitrided steel showed the best wear resistance even under a heavy load. Among the CrN films of 3,10 and 19 mum, the CrN film with a thickness of 10 mum showed the minimum wear loss and the wear loss of CrN film with a thickness of above 10 mum coated onto the untreated steel decreased nearly to that of CrN film coated onto the prenitrided steel.(4) The cermet films of CrNi-N coated onto the untreated steels show the good wear resistance and these films coated onto the pre-nitrided steels exhibet the inferior wear resistance compared with ones coated onto the untreated steels, being contrary to the tendency of the common ceramic films like as CrN.