THE EFFECT OF WEAR MECHANISM FOR PLASMA OXIDISED CP TI AND ITS ALLOYS ON TRIBOCORROSION PERFORMANCE

THE EFFECT OF WEAR MECHANISM FOR PLASMA OXIDISED CP TI AND ITS ALLOYS ON TRIBOCORROSION PERFORMANCEAbstract Commercially pure titanium (cp-Ti) and its alloys (Ti6Al4V, Ti45Nb, Ti6Al7Nb etc.) have an important use among biometallic materials. Recently developed alloying techniques and production methods have enabled many different titanium alloys to be used as biomaterials. Although harder and higher corrosion resistance than iron and its alloys, it is used as an invasive implant by applying various surface modifications to improve biodegradability performance. One of these processes is plasma oxidation process. With this process, corrosion resistance can be improved by obtaining more passive surfaces. There are many studies on these performance measurements in the literature. In this study, the effects of wear and corrosion mechanisms on the material in one cycle were investigated. Cp-Ti, Ti6Al4V and Ti45Nb were chosen as base materials. Samples were subjected to plasma oxidation for 600˚C-3 hours. Within the scope of this investigation, the adhesive wear mechanism on oxidized surfaces was compared with different types of abrasives, and its effect on corrosion performance was measured with the tribocorrosion test apparatus. Abrasion tests were carried out with two abrasive balls: tungsten carbide (WC) and silicon nitride (SiN) under 3 N load. Processes were carried out in two different media, dry and simulated body fluid (SBF). Potentiodynamic polarization scans were carried out using the scanning range of -0.28 V - 2 V in the presence of wear tests for tribocorrosion measurements. While abrasive wear mechanism is dominant in untreated samples, adhesive wear is at the forefront in coated samples. The effects that increase the corrosion resistance positively affected the performance of tribocorrosion. The high oxidation resistance of Ti and its alloys increased adhesive wear performance, and because of the higher corrosion resistance of Ti6Al4V and Ti45Nb, which were alloyed from these three material groups, their corrosion performance was higher than Cp-Ti.Keywords: Cp-Ti, Ti6Al4V, Ti45Nb, Plasma oxidation, Tribocorrosion

INVESTIGATION ON LEISURE BETWEEN THE YEARS 2009-2020 OF THE SCIENTIFIC STUDIES WITH TEACHERS IN TURKEY

Bu araştırmada, 2009-2020 yılları arasında Türkiye’de öğretmenler ile yapılan serbest zaman konulu bilimsel çalışmaların incelenmesi amaçlanmıştır. Araştırmada, nitel araştırma yöntemlerinden biri olan içerik analizi tekniği kullanılmıştır. YÖK Tez, Ulakbim, Google Akademik, Web of Sciences ve Eric veri tabanlarında, araştırma konusu ile ilgili yayımlanan lisansüstü tezler ve makaleler serbest zaman, boş zaman, rekreasyon ve öğretmen anahtar kelimeleri ile taranmış ve ulaşılan 18 yüksek lisans tezi ile 17 makale incelemeye tabi tutulmuştur. Belirlenen çalışmalar yıl, konu içeriği, cinsiyet, tür, yöntem, veri toplama aracı, kapsam büyüklüğü, öğretmenlerin çalıştıkları okul kademeleri, örneklem türü ve büyüklüğü temaları altında incelenmiştir. Elde edilen veriler SPSS20 programı kullanılarak, frekans ve yüzde değerleri analiz edilip tablolar halinde sunulmuştur. Araştırma sonucunda, en fazla çalışmanın 2019 yılında yapılmakla birlikte diğer yıllarda sadece birkaç çalışmanın yapıldığı ve doktora tezi olarak hiç çalışmanın yapılmadığı belirlenmiştir. Sonuç olarak, öğretmenler ile serbest zaman konulu yapılan çalışmaların sayısının arttırılması, doktora tezi düzeyinde de ele alınması, nitel ve karma yöntemlere ağırlık verilmesi, farklı il, coğrafi bölge ve koşullarda görev yapan öğretmenlerin serbest zaman değerlendirmelerine yönelik karşılaştırmalı çalışmaların yapılması önerilmektedir.In this study, is aimed to examine the scientific work between the years 2009-2020 on leisure with teachers in Turkey. Content analysis technique, one of the qualitative research methods, was used in the study. In YÖK Thesis, Ulakbim, Google Scholar, Web of Sciences and Eric databases, the postgraduate theses and articles published on the research topic were scanned with the keywords leisure, recreation and teacher and reached 18 master theses and 17 articles were examined. The studies determined were examined under the themes of year, subject content, gender, type, method, data collection tool, extent size, the school levels teachers work at, sample type and size. The data obtained were analyzed by using SPSS 20 program, their frequency and percentage values were analyzed and presented in tables. As a result of the research, it was determined that although the most studies were done in 2019, only a few studies were conducted in other years and no studies were conducted as a doctoral dissertation. As a result, it is recommended to increase the number of studies on leisure with teachers, to consider them also at the level of doctoral dissertation, to focus on qualitative and mixed methods, and to make comparative studies about leisure with teachers who work in different provinces, geographic regions and conditions