Abstract
Ceramic materials possessing the properties of high-strength and rigidity are widely used in industry. The shell nacre has a layered structure containing both macroscopic and microscopic levels and is equipped with superior qualities regarding hardness and strength. Therefore, the ceramic composites with a nacre-like layered structure have the potential to be utilized as sliding bearings employed in the harsh conditions of wells. For the purpose of this paper, a porous Al2O3 ceramics skeleton with nanometer powder is prepared using the freeze-casting method. Then the porous ceramic skeleton is filled with polymer polymethyl methacrylate (PMMA) through mass polymerization to produce a bionic Al2O3/PMMA composite with a lamellar structure. The properties of the prepared composite are determined by the analysis of micro-hardness, fracture toughness, friction coefficient, wear scar diameter, and the morphology of the worn surface. Consequent results indicate that elevation in the A12O3 powder, which acts as the initial solid phase content, prompts the ceramic slurry to exhibit an increase in viscosity and a gradual decrease in the pore size of the ceramic skeleton. The prepared layered Al2O3/PMMA composite possesses high fracture toughness, which closely resembles that of Al, is approximately four times that of the matrix of the Al2O3 ceramics and 16 times that of the PMMA. Three kinds of composites containing different solid phase content are subjected to testing involving lubrication by water-based drilling fluid to determine the friction coefficient of each. The results indicate that an increased load leads to a decreased friction coefficient while the impact of speed is not evident. Under dry conditions, the friction coefficient of three different composites tested, declines with elevated load and speed. With the use of water-based drilling fluid as lubrication, the wear scar diameter increases at higher speed, while dry conditions denote increased load. Abrasive wear is determined to be the principal form of erosion of layered Al2O3/PMMA composites.
Highlights
Bearings are essential components of downhole tools that are constantly exposed to extreme working conditions [1]
The porous ceramic skeleton is filled with polymer polymethyl methacrylate (PMMA) through mass polymerization to produce a bionic Al2 O3 /PMMA composite with a lamellar structure
Consequent results indicate that elevation in the A12 O3 powder, which acts as the initial solid phase content, prompts the ceramic slurry to exhibit an increase in viscosity and a gradual decrease in the pore size of the ceramic skeleton
Summary
Bearings are essential components of downhole tools that are constantly exposed to extreme working conditions [1]. The growth of ice crystals produced a micro-roughness on the surface of the ceramic wall equivalent to that of the nacre layer This structure could be effective in preventing slipping and improving the fracture toughness of materials. The study of shell nacre biomimetic ceramic composites has improved the strength, hardness, and toughness of the matrix material to a great extent, and shows excellent development potential, some problems are evident. Research into the compression strength, fracture toughness, micro hardness performance, and friction and wear properties, allowed for the material ratio and process parameters to be optimized, providing a wear-resistant sliding bearing composite material of exceptional strength. The water-based drilling fluids were deionized water.forThe bentonite was added with the glass rod mixing edge, found followed by the low prepared the harsh working conditions like the high water and sand content in oil/gas viscositywells.
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