Plazma spreylenmiş Cr3C2-NiCr ve Al203-TiO2 kaplamaların abraviz aşınma davranışlarının incelenmesi
Başlık çevirisi mevcut değil.
- Tez No: 55495
- Danışmanlar: DOÇ.DR. HÜSEYİN ÇİMENOĞLU
- Tez Türü: Yüksek Lisans
- Konular: Metalurji Mühendisliği, Metallurgical Engineering
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 1996
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 88
Özet
ÖZET Bu çalışmada plazma sprey kaplama yöntemi kullanılarak çeşitli metalik malzemeler üzerine kaplanmış seramik esaslı Cr3C2-NiCr ve AI2O3- Ti02 kaplamaların abraziv aşınma davranışları incelenmiştir. Pirinç, karbon çeliği, paslanmaz çelik ve takım çeliği üzerine yapılan krom karbür-nikel krom ve alumina-titanya plazma sprey kaplamaların abraziv aşınma deneylerinde hem krom karbür- nikel krom nemde alumina- titanya kaplamalarda en düşük aşınma altlık malzeme paslanmaz çelik olduğunda elde edilmiştir.. Altlık malzemelerin abraziv aşınma açısından kaplamaya uygunluk sırası paslanmaz çelik, takım çeliği, karbon çeliği ve pirinç şeklinde geçekleşmiştir. Ayrıca her iki kaplamanın altlık malzemenin aşınma direnci üzerindeki etkisi kaplamanın yüzey pürüzlülüğüne bağlıdır. En yüksek aşınma direnci yüzey pürüzlülüğü en düşük olduğunda elde edilmektedir. Hacim kaybı kriter alındığında krom karbür- nikel krom kaplamanın alumina-titanya kaplamadan abraziv aşınmaya karşın bir miktar daha dirençli olduğu saptanmıştır. XI
Özet (Çeviri)
THE INVESTIGATION OF ABRASIVE WEAR BEHAVIOURS OF PLASMA SPRAYED Cr3C2-NiCr AND Al203-Ti02 COATINGS SUMMARY Since many forms of attack such as corrosion, friction, wear, heat, radiation occur on the surface of a component, or transferred via the surface into the component, surface protection has a considerable significance as regards modern materials technology. The purpose of surface technology is to produce functionally effective surfaces. This implies matching the surface properties of a component to its particular operating stresses. The aim is to achieve improvements of operating life, reliability, economic performance, safety and outputs from products and processes. Plasma spraying has a particularly high potential in the solution of complete material problems. It is possible using this method to coat components with any type of material. Coatings can be applied technically on to all suitable base materials, irrespective of whether the component is small or large, a high degree of automation can be easily accomplished and the spray process integrated into fabrication sequences both for mass and individual production. Plasma spraying is one of a family of techniques known generically as“ thermal spraying”. In such processes the material to be sprayed is heated rapidly until it is substantially molten and is then projected at high velocity onto a suitably prepared surface where it adheres to give the desired coating. In the plasma processes the heat source is an electric arc struck between two electrodes, the anode of which serves as a nozzle. By suitable design the arc is constricted and stabilized within the latter, generating temperatures up to 20000 °K with the ionized gases being ejected at high velocities of several hundred meters per second. This arc plasma is a source of high thermal and kinetic energy to entrained material. Most guns use nitrogen, argon or helium as the main plasma gas and operate at power levels between 20 and 80 kW. The coating material is injected in powder form into the plasma, at a position mainly determined by its melting point. Because of the high temperature and inert nature of the plasma and since the dwell times are less than millisecond, almost any material can be sprayed provided it melts without significant dissociation or evaporation. A wide range of materials, ceramics and some plastics can be sprayed. However, an important pre- XIIrequisite for successful plasma spraying, especially with ceramic materials, is to have well-characterized free-flowing powders. The high temperature achieved in thermal plasmas allow the melting of any material, which does not decompose or vaporize excessively, within a very short time interval. For this reason, plasma spraying of ceramic coatings has become well established a commercial processes over the past 25 years. In plasma spray processes; -The temperature of the part to be coated can be kept at a values of less than 200 ° C by cooling even where thin walled sheet metal is concerned. The following advantages are gained in this way: - No distortion, so that finish machined parts can be coated - No change of microstructure in the base material - No oxidation of parts made from low melting point alloys, such as aluminum, tin and zinc alloys, as well as from selected plastics, is possible. -Coating material and base material can be selected and combined independently of each other. The composition, configuration and properties of the plasma spray layers can be varied over a wide range and thus optimized to the particular application. -Localized coatings with suitable layer thickness can be applied to areas subjected to high stress. Hence a considerable degree of saving of expensive materials possible. - Plasma spraying can be used for coating large and small parts, in mass production and in one-off fabrication. - A high degree of automation of the plasma spray process can be achieved, so that the economic performance and the economic performance and the reproducibility of high coating quality are assured. Plasma spray technology, being used essentially materials engineering, has a great potential in connection with: - improvement of the performance of parts and machine components by pairing of optimum base material and coating properties, so as to obtain a combination of characteristics which would not be possible with possible materials. - lowering of costs, since inexpensive base materials are improved by high grade coatings. XIII- best use of resources, by sparing use of materials which are expensive, rare or otherwise difficult to obtain - innovation of technical products, by the provision of new fabrication possibilities and component properties, as well as new product characteristics. The plasma spraying processes is a technique that combines particle heating, quenching and consolidation into a single processes. The arc plasma spraying process involves injection of powder particles in to a plasma jet undergo rapid melting and at the same time are accelerated toward the work piece surfaces rapid quenching of the molten particulate occurs when the droplets impact the surface. Cooling rates are typically 105- 106 °K/s, and the resulting microstructures are fine grained but may retain a substantial amount of porosity. Plasma sprayed coatings offer technical advantages over other coating processes: - High particle velocities result in higher bong strength coupled with higher coating density. - The heat source is more efficient, because a plasma due to dissociation and ionization processes, is a very high state. For this reason, high energy supplied to the particles accompanied by a minimum temperature drop in the surrounding gas stream, thus providing efficient heating. -The heating source is inert, minimizing oxidation. - High plasma temperatures permit the spraying of materials with high melting points. Even though plasma spraying is a costly technique, the market for the coatings produced will have more than doubled with in the next then years. The superior properties of the films and their ability to provide solutions unattainable by other methods makes these processes most attractive. These coatings can also be prepared with a high deposition rate while maintaining excellent reproducibility. Depending on the pressure level, the chemical composition of the environment and the type of electrical arc, the plasma spray process is divided into the following types: atmosphere, vacuum, inert gas, underwater and inductive coupled plasma spray. XIVThe analysis of the plasma sprayed coatings show that coatings has a lamellae structure and the interface between lamellae consists of regions of perfect contact and regions in which there are gaps of 0.01-0.10 urn. The coating thus exhibits different thermal and mechanical behavior from other materials or from a material which is bulk processed. For example the thermal conductivity of these coatings is much lower than the bulk processed material. The atmosphere in which the spraying takes place has a decisive influence on the properties of the plasma spray coatings. - In APS (Atmospheric Plasma Spraying), spraying takes place under normal ambient conditions. Reaction between the spray powder particles and the air is markedly limited by the protective effect of the inert plasma jet and by the short transit times. Powders of certain metals or alloys can become oxidized to some extent on the surface. The oxide layers are integrated into the coating. Due to the extremely high coating solidification and cooling down speeds, plasma spray coatings are harder and more wear resistant than the material in powder form used to produce them. -In VPS (Vacuum Plasma Spraying), where extremely stringent requirements concerning density, purity and freedom from oxide are imposed, the spray process has to be carried out in a chamber in an inert atmosphere. Where plasma spraying is carried out in the presence or argon at less than atmospheric pressure, undesirable reactions between the atmosphere and the plasma jet, spray coating or base material are eliminated. The coatings are formed at higher energy, since the particulates are less cooled and less slowed down during their passage through the gas at reduced pressure than under standard condition. Improved coatings having the highest values of density, adhesion and cohesion, together with optimum structure are the result. All substances which comply with the following requirements are suitable as spray materials for the production of plasma spray coatings: - The spray material must melt without changing in any desired way, e.g., no degradation, sublimation or oxidation - The spray material must be producible as powder in a form suitable for spraying, e.g., grain shape, grain size and size distribution. At present, several hundred different materials are plasma sprayed. They can be classified as pure metals, alloys, pseudo-alloys, ceramics, cermets and plastics. XVDepending on the composition, combination and mixing ratio of the various spray material components, layers with unusual characteristics can be produced by plasma spraying. Such layers cannot be obtained either by the classic coating processes or with homogeneous traditional materials. In this work, abrasive wear behaviours of Cr3C2-NiCr and Al203-Ti02 coatings coated on brass, low carbon steel, stainless steel and tool steel substrates were studied. Coatings were investigated with various techniques given below; - X-Rays Diffraction Analysis, - Metallographic Invesgation, - Microhardness Testing, - Surface Roughness Measurement, - Three-Point Bending Test, - Friction Coefficients Measurement, The experimental results can be summarized as follows; 1 -X-Rays analysis showed that plasma sprayed coatings could have different phases than the initial powder coating material. This is due to the high temperatures of plasmas and performing spraying in ambient atmosphere. 2-Metallographic investigations revealed that coatings had laminar microstructures and contained defects such as pores, unmelted particulates and semi molten particulates. 3- Bonding strength of the coatings on substrates were evaluated by three- point bending tests. Three point bending tests revealed that; -The coatings coated on stainless steel had the best bond strength. -Cr3C2-NiCr coatings had higher bond strength than Al203-Ti02 coatings. 4- Both Al203-Ti02 and Cr3C2-NiCr coatings coated on stainless steel had the best abrasive wear resistance. When these coatings coated on brass they had the worst wear resistance. 5- The wear resistance of the coatings increased with decreasing surface roughness of the coating. 6- The increment in wear resistance of a material by coating, decreased with decreasing hardness of the substrate. When the hardness of the substrate was low, superiour increment in wear resistance was obtained. XVI
Benzer Tezler
- Fonksiyonel derecelendirilmiş Al2O3 CYZS termal bariyer kaplamaların cmas ve sıcak korozyon özelliklerinin belirlenmesi
Determination cmas and hot corrosion properties of functionally graded Al2O3 CYSZ thermal barrier coatings
FATİH KIRBIYIK
Doktora
Türkçe
2023
Metalurji Mühendisliğiİstanbul Teknik ÜniversitesiMetalurji ve Malzeme Mühendisliği Ana Bilim Dalı
PROF. DR. GÜLTEKİN GÖLLER
- Plazma homosistein, folat vitamin B12 ile prematüre koroner arter hastalığı arasındaki ilişki üzerine bir araştırma
Plasma homocystine, folate, vitamin B12, relation between premature coronary artery disease
AHU ŞEBNEM ONUR
Yüksek Lisans
Türkçe
1999
Beslenme ve DiyetetikHacettepe ÜniversitesiDiyetetik Ana Bilim Dalı
PROF. DR. NAZAN BOZKURT
- Plazma proteinleri arasındaki ilişkinin kimyasal çapraz bağlama yöntemiyle değerlendirilmesi
The Definition of relation between the plasma proteins by the chemical cross-linking method
EDA BALTACIOĞLU
- Plazmanın temel denklemleri ve yüklü parçacıklarla etkileşmeleri
Başlık çevirisi yok
FATMA CANSEVEN
Yüksek Lisans
Türkçe
1998
Fizik ve Fizik MühendisliğiAnkara ÜniversitesiFizik Mühendisliği Ana Bilim Dalı
DOÇ. DR. FATMA ERDOĞAN
- Plazma nitrürlenmiş ve beyaz tabakası kaldırılmış AISI H13 ve 722M24 çeliklerinin farklı aşınma özelliklerinin incelenmesi
The Investigation of wear behaviour of plasma nitrided and removed white layer of AISI H13 and 722M24 steels at the different
EYYÜP GERÇEKCİOĞLU
Doktora
Türkçe
1998
Makine MühendisliğiErciyes ÜniversitesiMakine Mühendisliği Ana Bilim Dalı
PROF. DR. M. BAKİ KARAMIŞ