CrAlN thermal insulation coating for aluminum alloy piston combustor surface and preparation method thereof

A technology of thermal insulation coating and combustion chamber, applied in metal material coating process, coating, ion implantation plating, etc., can solve the problems of poor bonding force between aluminum alloy and thermal insulation coating, corrosion, thermal fatigue, etc. , to achieve the effect of low intrinsic thermal conductivity, improved bonding force, and reduced stress

Active Publication Date: 2018-11-02
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the deficiencies in the prior art above, the purpose of the present invention is to provide a CrAlN heat-insulating coating for the combustion chamber surface of an aluminum alloy piston and a preparation method thereof, so as to solve problems caused by poor bonding of the base material aluminum alloy and the heat-insulating coating. , resulting in the failure behavior of the piston due to thermal load, thermal fatigue and thermal corrosion caused by the harsh service environment

Method used

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  • CrAlN thermal insulation coating for aluminum alloy piston combustor surface and preparation method thereof
  • CrAlN thermal insulation coating for aluminum alloy piston combustor surface and preparation method thereof
  • CrAlN thermal insulation coating for aluminum alloy piston combustor surface and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0053] 1) Preparation of transition layer

[0054] Put the pretreated aluminum alloy piston into the magnetic filter cathode vacuum chamber, adjust the positive bias voltage to 2.4V, the upper deflection current 2.4 A, the lower deflection current 3.2 A, and the duty cycle of 86.2±0.1%. 25 Al 75 The target is the cathode, and the arc starting current is adjusted to 100A, and five negative pressure points of -600 V, -500 V, -400 V, -300 V and -200 V are used in sequence, and the surface of the pretreated substrate is sputtered The CrAl transition layer was deposited in the manner of ", and each negative pressure point was maintained for 30 s to 60 s, and then the negative bias was selected to be -50V to continue depositing the CrAl transition layer. The deposition time was 20 min, and CrAl was deposited on the surface of the aluminum alloy piston. form a transition layer.

[0055] 2) Preparation of insulation layer

[0056] On the transition layer obtained in step 1), contin...

Embodiment 2

[0061] 1) Preparation of transition layer

[0062] Put the pretreated aluminum alloy piston into the magnetic filter cathode vacuum chamber, adjust the positive bias voltage to 2.4 V, the upper deflection current to 2.4 A, the lower deflection current to 3.2 A, and the duty cycle to be 86.2±0.1%. 25 Al 75 The target is the cathode, the arc starting current is adjusted to 100 A, and five negative pressure points of -600 V, -500 V, -400 V, -300 V and -200 V are sequentially used to sputter The CrAl transition layer was deposited in the manner of ", and each negative pressure point was maintained for 30 s to 60 s, and then the negative bias was selected to be -50V to continue depositing the CrAl transition layer. The deposition time was 20 min, and CrAl was deposited on the surface of the aluminum alloy piston. form a transition layer;

[0063] 2) Preparation of insulation layer

[0064] On the transition layer obtained in step 1), continue to use the magnetic filter cathode v...

Embodiment 3

[0069] 1) Preparation of transition layer

[0070] Put the pretreated aluminum alloy piston into the magnetic filter cathode vacuum chamber, adjust the positive bias voltage to 2.4V, the upper deflection current to 2.4A, the lower deflection current to 3.2A, and the duty cycle to be 86.2±0.1%. 25 Al 75 The target is the cathode, the arcing current is adjusted to 100A, and 5 negative pressure points of -600 V, -500 V, -400 V, -300 V and -200 V are sequentially used to "sputter" on the surface of the pretreated substrate The CrAl transition layer was deposited in the same way, and each negative pressure point was kept for 30 s to 60 s, and then the negative bias was selected to be -50 V to continue depositing the CrAl transition layer. The deposition time was 20 min, and CrAl was deposited on the surface of the aluminum alloy piston. form a transition layer;

[0071] 2) Preparation of insulation layer

[0072] On the transition layer obtained in step 1), continue to use the m...

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Abstract

The invention discloses a CrAlN thermal insulation coating for an aluminum alloy piston combustor surface and a preparation method thereof. The CrAlN thermal insulation coating comprises a transitionlayer and a thermal insulation layer from the inside out in order, the transition layer is a CrAl coating, and the thermal insulation layer is a CrAlN coating. The method adopts filtered cathodic vacuum arc technique, takes a CrAl alloy target material (Cr, Al metal target) as the cathode, performs deposition of the CrAl coating on the aluminum alloy surface to form a transition layer, then uses nitrogen as the working gas, and coats the transition layer surface with the CrAlN coating evenly to form the thermal insulation layer. The CrAlN thermal insulation coating provided by the invention not only solves the problem of poor binding force and bearing ability caused by large difference of basic physical properties between the CrAlN coating and the aluminum alloy substrate material, also the coating is uniform and compact, has good film-substrate combination state and hardness up to 40GPa, and shows good high temperature thermal insulation properties and thermal shock resistance in piston thermal load test. The CrAlN thermal insulation coating provided by the invention significantly improves the performance reliability and service life of the aluminum alloy piston, and can meet thehigh power and low emission development requirements of modern engines.

Description

technical field [0001] The invention relates to the field of piston surface treatment, in particular to a CrAlN heat-insulating coating for an aluminum alloy piston combustion chamber surface and a preparation method thereof. Background technique [0002] The piston is the "heart" of the engine and an important component for the engine to transmit energy. The quality of the piston directly affects the usability, economy and life of the engine. Among them, when the piston combustion chamber surface is located at the top dead center, it is above the top surface of the piston and below the bottom surface of the cylinder head. It is used to mix gas, organize air flow and provide space for combustion. However, diesel engine fuel has a high viscosity and is not easy to evaporate, and its autoignition temperature is lower than that of gasoline. The working nature of piston compression ignition endows the combustion chamber with a more severe service environment. When the piston of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C14/32C23C14/06C23C14/02
CPCC23C14/0021C23C14/025C23C14/0641C23C14/325
Inventor 齐福刚李贝贝欧阳晓平赵镍曹红帅罗文忠钟向丽陈静刘应都王冰
Owner XIANGTAN UNIV
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