Publication: Nitrasyon ve katodik ark PVD yöntemi ile oluşturulan TiCrN ince film kaplamaların incelenmesi
Abstract
Fiziksel buhar biriktirme yöntemiyle biriktirilen geleneksel ikili nitrür kaplamalar endüstrinin birçok alanında kullanılmıştır. Ancak gelişen teknoloji ve artan rekabet daha verimli çalışma koşullarını gerektirir. Bu durum geleneksel ikili nitrür kaplamalardan daha üstün özelliklere sahip kaplama yapılarına olan ihtiyacı doğurmuştur. Aşınma direnci daha iyi olan kaplamalar için çok katmanlı yapıların yanı sıra bir yüzey sertleştirme prosesinden sonra kaplamanın yüzeye biriktirilmesi üzerine olan çalışmalar yoğunlaşmıştır. Bu çalışma kapsamında endüstride sıklıkla kullanılmakta olan DIN 1.2379 ve DIN 1.2344 takım çelikleri üzerine tek katmanlı ve çok katmanlı TiCrN kaplamaları uygulanmıştır. Hem tek katmanlı hem de çok katmanlı kaplama prosesi nitrasyon uygulanmış olan takım çelikleri üzerinde de tekrarlanmıştır. Kaplama katman sayısının ve nitrasyon işleminin kaplama mekanik özelliklerine olan etkisi değerlendirilmiştir.Kaplama işleminin ardından, üretilen kaplamaların kalınlıkları calotest yöntemiyle, morfolojik yapıları ise taramalı elektron mikroskobu ile incelenmiştir. Kaplamaların faz analizi için X ışını difraksiyonu, sertlikleri için ultra mikrosertlik, adhezyon özellikleri ise Rockwell C indentasyon yöntemiyle belirlenmiştir. Kaplamaların aşınma özelliklerini belirlemek amacıyla tribometre cihazında 5N, 10N ve 15N yük koşulunda aşınma testleri uygulanmıştır. Aşınma izlerinin morfolojik yapılarını incelemek için optik mikroskop ve atomik kuvvet mikroskobu kullanılmıştır, elementsel analizlerinin belirlenmesi için ise SEM EDS analizi yapılmıştır. Ayrıca aşınma hacimlerinin ve maksimum iz derinliklerini elde etmek için izler üç boyutlu optik profilometre cihazında incelenmiştir. Yapılan incelemeler sonuçta kaplamalı olan numunelerin, kaplamasız ve nitrasyonlu numuneye kıyasla üç yük koşulunda da daha iyi aşınma direnci sergiledikleri görülmektedir. Nitrasyon işlemi sonrasında tek ve çok katmanlı TiCrN kaplama uygulanan numunelerde adhezyon özelliklerinin iyileştiği ve aşınma oranlarının daha düşük olduğu, ancak kaplama yapısının tek veya çok katmanlı olmasının uygulanan yük koşullarında belirgin bir farklılık göstermediği sonuca varılmıştır.
Conventional dual nitride coatings have been widely used in the industry using the physical vapor deposition (PVD) method. However, further improvement of this technology requires higher process efficiency to meet the demands of increased competition. This has led to the need for novel structures that have superior properties to the conventional dual nitride coatings. In order to produce coatings with better wear resistance, recent studies have concentrated on the deposition of the coatings after a surface hardening process as well as deposition of multilayered coatings. In this thesis work, monolayer and multilayer TiCrN coatings were applied on DIN 1.2379 and DIN 1.2344 grade tool steels, which are frequently used in the industry. Both the monolayer and multilayer coating processes were also applied on tool steels with nitration. The effect of the number of coating layers and nitration treatment on coating mechanical properties was investigated. After the coating process, the thicknesses of coatings and morphological structures were examined by calotest method and scanning electron microscopy (SEM), respectively. Phase analysis of coatings was determined by X-ray diffraction, hardness values were determined by ultra microhardness device and adhesion properties were determined by Rockwell C indentation method. Wear properties of the coatings such as coefficient of friction and wear volume were determined using a tribometer under 5N, 10N and 15N loads. Optical microscopy and atomic force microscopy (AFM) were used to examine the morphological structures, while the SEM EDS analysis was performed to determine the elemental analysis of the wear scars. In addition, scars were examined in a three dimensional optical profilometer in order to obtain wear volumes and maximum scar depths. Results of analysis indicate that the coated samples have better wear resistance in all three load conditions compared to uncoated and nitrated samples. The adhesion properties are also improved and wear rates are lower in samples applied with monolayer and multilayer TiCrN coating with nitration process. However, the difference in number of coating layers does not play a significant role on the final mechanical properties.
Conventional dual nitride coatings have been widely used in the industry using the physical vapor deposition (PVD) method. However, further improvement of this technology requires higher process efficiency to meet the demands of increased competition. This has led to the need for novel structures that have superior properties to the conventional dual nitride coatings. In order to produce coatings with better wear resistance, recent studies have concentrated on the deposition of the coatings after a surface hardening process as well as deposition of multilayered coatings. In this thesis work, monolayer and multilayer TiCrN coatings were applied on DIN 1.2379 and DIN 1.2344 grade tool steels, which are frequently used in the industry. Both the monolayer and multilayer coating processes were also applied on tool steels with nitration. The effect of the number of coating layers and nitration treatment on coating mechanical properties was investigated. After the coating process, the thicknesses of coatings and morphological structures were examined by calotest method and scanning electron microscopy (SEM), respectively. Phase analysis of coatings was determined by X-ray diffraction, hardness values were determined by ultra microhardness device and adhesion properties were determined by Rockwell C indentation method. Wear properties of the coatings such as coefficient of friction and wear volume were determined using a tribometer under 5N, 10N and 15N loads. Optical microscopy and atomic force microscopy (AFM) were used to examine the morphological structures, while the SEM EDS analysis was performed to determine the elemental analysis of the wear scars. In addition, scars were examined in a three dimensional optical profilometer in order to obtain wear volumes and maximum scar depths. Results of analysis indicate that the coated samples have better wear resistance in all three load conditions compared to uncoated and nitrated samples. The adhesion properties are also improved and wear rates are lower in samples applied with monolayer and multilayer TiCrN coating with nitration process. However, the difference in number of coating layers does not play a significant role on the final mechanical properties.