Effect of Hf addition on reciprocating wear performance of ZrN coatings

Abstract

Bu çalışmada, ZrN ve (Zr, %12 Hf)N kaplamaların aşınma davranışları incelenmiştir. Kaplamalar Zr ve %21Hf alaşımlı Zr katotların kombinasyonu ile üretilmiştir. Üretilen kaplamaların aşınma deneyleri, karşılıklı kazımalı aşınma deney cihazında, 1.5 N sabit yük altında ve 0.02 mm/s deney hızında 10 mm çapındaki Al2O3 bilyenin numune yüzeylerine sürtünmesi ile gerçekleştirilmiştir. Deney sonrası numune yüzeyinde oluşan aşınma izleri, yüzey profilometresi yardımı ile incelenmiş ve deney sonuçları aşınma iz alanları ölçülerek mm2 cinsinden alan kaybına göre değerlendirilmiştir. Deney sonuçları, (Zr, %12 Hf)N kaplamanın ZrN kaplamaya göre daha az aşındığını ve Hf ilavesinin aşınmaya karşı direnci artırdığını  göstermiştir.Anahtar Kelimler: Kaplama, FBB, ZrN, Hf, aşınma.In this study, a commercial ZrN and new (Zr, Hf)N coatings by alloying ZrN with Hf were deposited on hardened AISI D2 quality cold work tool steel plates by arc PVD technique. The coatings were prepared using combination of two cathodes under the equvalent PVD process conditions. ZrN and (Zr, %12 Hf)N coatings were obtained by utilising two Zr cathodes and one Zr and one Zr+21% Hf cothodes, respectively. The characterisation of the coatings were made by Scanning Electron Microscopic (SEM) examinations, X-ray diffraction analyses (XRD), hardness and adhesion tests as well as roughness and thickness measurements. Hardness measurements were carried out ultramicrohardness tester with a Vickers pyramid indenter. The indentation procedure consisted of 60 steps, with a waiting period between consecutive steps of 1 s. During the tests, load (P)-indentation depth (h)-time (t) data were recorded. Hardness measurements were performed under constant load of 25 mN. In order to investigate adhesion properties of the ZrN and the (Zr, 12% Hf)N coatings, scratch tests were used. The coatings were scratched up to 100 N normal load by using 10 mm/min scratching speed and 100 N/min loading speed. The dry sliding wear behaviour of ZrN and (Zr,12%Hf)N were examined by a reciprocating wear tester in ambient atmoshper. Alloying of ZrN coating with 12% Hf did not change the hardness significantly, but achieved an improvement on adhesion strength and wear resistance.Keywords: Coating, PVD, ZrN, Hf, wear

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