Vpliv kemotermične obdelave podlage na tribološke lastnosti trdih prevlek

B. Podgornik, J. Vižintin

Strojniški vestnik 47 (2001) 152–162.

Abstract

V raziskavi so bile določene tribološke lastnosti jekla 42CrMo₄, nitriranega v plazmi in prekritega z različnimi zaščitnimi prevlekami (TiN, TiAIN in DLC). Pred tribološkimi preskusi smo z elektronsko in optično mikroskopijo, z merjenje mikrotrdote ter oprijemljivosti prevlek vrednotili dotikalno tehnično površino. Tribološke preskuse smo opravili na napravi "valjček-disk" pri suhem drsenju. Za ugotovitev vpliva nitriranja, njegove globine in spojinske plasti na tribološke lastnosti sestave prevleka-podlaga smo trde zaščitne prevleke nanesli na kaljeno jeklo, nitrirano v plazmi. Samo nitriranje v plazmi je bilo izvedeno v različnih razmerah. Rezultati kažejo, da v primerjavi z kaljenjem, nitriranje jekla 42CrMo₄ izboljša protiobrabno odpornost nanesenih trdih zaščitnih prevlek. Poleg tega natančno voden proces nitriranja v plazmi omogoča nastanek homogene spojinske plasti, ki ima pozitiven učinek na protiobrabne lastnosti trde zaščitne prevleke.

In the research, samples made of AISI 4140 steel pre-treated by plasma nitriding and coated with different PVD coatings (TiN, TiAIN and ta-C)were investigated in terms of their microhardness, scratch adhesion and dry sliding wear resistance. Wear tests, in which duplex-treated pins were mated to hardened ball bearing steel discs, were performed with a pin-on-disc machine. To examine the influence of the nitrided zone on the performance of the coating-substrate composite, coatings were deposited on hardened as well as on plasma nitrided samples, prepared under different nitriding conditions. The results of the investigation showed improved mechanical and tribological properties of the plasma nitrided hard-coated specimens compared to the un-coated and pre-hardened ones. Furthermore, the compound layer was found to act as an intermediate hard layer leading to superior sliding wear properties of the composite.

Keywords: plasma nitriding, hard coatings, dry sliding, wear

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