2011 YÜksek lisans tez özetleri

Electrochemical Production and Characterization on Nickel-SiC Composite Coatings

In thesis study, pure Ni and Ni/SiC composite coatings were produced on brass plates from Watts type nickel bath by using electrochemical technique. In the production of Ni/SiC composite coatings, the effect of electrochemical parameters such as current density, temperature, pH value of electrolyte, bath stirring rate, composition and size of SiC particles on composite coating performance were investigated.

Ni/SiC composite coatings were made in three different experimental setups dependent on SiC co-deposition. The first type of Ni/SiC coatings were electroplated in electrolyte by adding SiC powders in three different sizes and between 5-100 gL^-1 particle concentration. In this first batch of experiments, the effects of concentration and size of SiC particles on corrosion properties of coatings were studied. The second type coatings (K type) were produced by addition of different particle sizes of SiC powders in determined ratios, the total concentration of which equals to 20 gL^-1, into the electrolyte. In these electroplating studies, powder mixture that consists of three different size of SiC particles were used. The third and the last type (G type) is multi-layer coating. G type coatings were sequentially plated in different plating baths that have SiC powders with different particle size and concentration.

Values used for various experimental parameters are given below:

• 
  SiC concentration : 0, 5, 10, 20, 50 and 100 gL^-1 (d_m=0.7 μm, 2 μm and 50 nm)
  
• 
  pH value of electrolyte : 2, 3, 4 and 5
  
• 
  Temperature : 30, 55 and 70⁰C
  
• 
  Current density : 2, 4, 5, 6 and 8 Adm^-2
  
• 
  Stirring speed : 120, 240, 360 and 480 rpm
  

Properties of resulting composite coatings such as microstructure, hardness, wear and corrosion resistance were determined by performing SEM (EDAX), XRD, corrosion, microhardness and wear tests. Current efficiency dependent on Ni⁺² concentration in electrolyte was also calculated by using atomic absorpsion (AA) device.


YELTEN Azade

Danışman : Prof. Dr. Suat YILMAZ

Anabilim Dalı : Metalurji ve Malzeme Mühendisliği

Mezuniyet Yılı : 2011

Tez Savunma Jürisi : Prof. Dr. Suat YILMAZ

Prof. Dr. İbrahim YUSUFOĞLU

Prof. Dr. Enver OKTAY

Prof. Dr. Şerafettin EROĞLU

Prof. Dr. Ercan AÇMA