Characteristics of plasma spray coatings
Journal Title: Vojnotehnički glasnik - Year 2019, Vol 67, Issue 1
Abstract
The characteristics of plasma spray coatings are directly related to the type of process applied (APS - atmospheric plasma spray, VPS - vacuum plasma spray, and SPS - suspension plasma spray), the characteristics of the powder and the powder deposition parameters. The properties of plasma spray coatings can be changed and adjusted depending on the operating conditions, i.e. the purpose of coatings. Applying the same powder in the deposition process can lead to coatings of different properties, depending on their purpose. If the deposited coating is intended for corrosion protection and biomedical application, it is necessary that the coating is compact. When the coating is deposited for the purpose of thermal insulation, it should be porous. Powder particles in the plasma are spherical liquid drops which, in collision with the substrate, form a lamellar structure of the coating. A higher degree of powder melting and a higher velocity of molten droplets lead to a denser structure of deposited layers. When colliding with the substrate, deposited particles transfer heat to a working part until cooling to ambient temperature. If the working part is cooled by compressed air, molten droplets solidify extremely quickly with columnar crystals in lamellae. The aim of this paper is to describe the influence of temperature and velocity of powder particles on the deformation and hardening of particles defined by the D/d ratio, chemical changes in molten particles as well as porosity, crystal changes, and internal stresses in coatings.
Authors and Affiliations
Mihailo Mrdak
Keywords
Related Articles
- EP ID EP438490
- DOI 10.5937/vojtehg67-16558
- Views 106
- Downloads 0
Compromising electromagnetic radiation: Challenges, threats and protection
The aim of this paper is to open up problems regarding parasitic radiation, both inductive and conductive one, originating from devices for data transmission, processing, generation and data protection as well as from th...
Muticriteria assessment of possible use of computer games in teaching
In this paper we present a multi-criteria evaluation of several possible approaches to organization of studies. A wider use of modern information technology has led to major changes in traditional education. One of them...
Mechanical properties and microstructures of bio-inert layers of chrome oxide coatings deposited by the APS process
Plasma spray Cr2O3 ceramic layers are used as a separate coating or as a supplement to bio-reactive organic composite ceramics Ca10(PO4)6(OH)2-Al2O3-ZrO2-Cr2O3 and other bio-inert ceramics in composites of the types Al2O...
Research of the effects of shock and vibrations on the human body
There is very little reliable information about the forces needed to cause injury to the human body. Namely, it is very difficult to obtain reliable reports about the influence of mechanical forces and the subjective rea...
Computer simulation of the 7.62mm TT pistol external ballistics using two different air resistance laws
A description of a pistol (rifle) cartridge often involves two ballistic coefficients that characterize its ballistic qualities with respect to various air resistance laws (ARLs). How close are the obtained ballistic tra...