Ni-Ti Akıllı Alaşım İnce Filmin Sıcaklığa Bağlı X-Ray Kırınımı ile Karakterizasyonu ve Faz Dönüşümü Tespiti

Abstract

zet-Günümüzün popüler konularından olan ince film akıllı alaşımlar, her geçen yıl ihtiyaç ölçüsünde daha da küçülen mikro elektromekanik sistemlerdir. Bu alaşımlardan NiTi ince film, sahip olduğu termoelastik özellikler sayesinde yaygın olarak tercih edilmektedir. Depolanan bu filmlerin fiziksel özelliklerinin anlaşılabilmesi için birçok karakterizasyon yöntemi mevcuttur. Bu çalışmada silikon altlık üzerine depolanmış Nikel-Titanyum ince filmin faz dönüşümü sıcaklığa bağlı X-Ray kırınımı ile incelenmiştir. İncelenen sıcaklık aralığı -125C ile 125C olarak alınmıştır. Stokiyometrik olarak birbirinden farklı iki NiTi örneği (oda sıcaklığında biri austenit diğeri martensit oranları daha yüksek olan) incelenmiş ve her bir filmin faz dönüşüm sıcaklıkları (austenit başlangıç ve bitiş, martensit başlangıç ve bitiş) tespit edilmiştir. Direkt karşılaştırma yöntemi kullanılarak işlem esnasındaki martensit hacim oranı sıcaklığa bağlı olarak elde edilmiştir. Anahtar Kelimeler-Şekil Hafızalı Alaşım, NiTi İnce Film, X-Işınımı Kırınımıbstract-Thin film shape memory alloy which is strongly relevant with the fabrication of the micro electro mechanical systems is one of the hot research topic in last decades. Among the investigated shape memory alloys, NiTi is stepping forward by the thermos-elastic features it has. In order to understand their physical properties, several characterization methods have been used by the researchers. In this study, a NiTi thin film that is deposited on a Si substrate is characterized by an X-Ray Diffraction under gradually evolving testing temperatures. The examination is performed between -125C and 125C. Two stoichiometrically different samples (at room temperature, one of them is martensite rich and the other is austenite rich) are tested and the phase transformation temperatures are determined (martensite and austenite start and finish temperatures) during the experiments. Furthermore, by using the direct comparison method, the martensite volume fraction is determined with regard to temperature.

Biosensors: Types, Applications, and Future Advantages

“…Biosensors with high reaction specificity characteristics are suitable for use in the medical field [85]. Biosensors are most used in the medical field as an application.…”

“…Microbial sensors are not used in biosensors in the medical field. Because these sensors work with biological fluids, these liquids, on the other hand, form the environment that allows microorganisms to reproduce [85]. There are also diagnostic areas that are of vital importance.…”

“…Especially in cities, its use in the control of environmental pollution and quality monitoring, and its use in the control of microorganisms and toxins is observed. At the same time, it is used in the measurement of organic impurities in water in [85]. Chemical analyzes and eco-toxicological tests are usually used to clean nature that has been polluted for various reasons.…”

“…The use of biosensors is the most preferred method at this point. The reason for the preference is that biosensors provide fast, reliable, and accurate results [85]. Biological weapons are a way that can be used against the state, as they can create a wide fuss and trouble for terrorists [88].…”

“…This angle increases if the cohesion force is greater than the adhesion force. Surfaces with a contact angle less than 90 o are known as hydrophilic, and those larger than 90 o are known as hydrophobic surfaces [85].…”