Aluminum alloy cylinder body inner surface ceramic layer and technique thereof

Abstract

The invention provides an aluminum alloy cylinder body inner surface ceramic layer and a technique thereof. The technique comprises the following steps: firstly prefabricating a threaded spiral groove in the inner surface of an aluminum alloy cylinder body by machining; and then respectively growing two layers of Al2O3 ceramic films in situ on the inner surface and the outer surface of the spiral groove by micro-arc oxidation. The ceramic layer consists of two layers, the bottom layer is a threaded spiral layer under the inner surface of the cylinder body, the depth of the bottom layer is 30-400 mu m, the ceramic layer on the inner surface of the cylinder body is a surface layer, and the thickness of the surface layer is 0-10 mu m. The ceramic layer is combined to a base body firmly, is high in hardness and compactness, not only has wear resistance, impact resistance and corrosion resistance, but also has good thermal conductivity. The ceramic films are prepared simply, and are easy to control, low in cost and high in efficiency.

Description

technical field [0001] The invention relates to the preparation of a ceramic layer on the inner surface of a cylinder and a process method thereof, in particular to the oxidation of Al on the inner surface of an aluminum alloy cylinder. 2 o 3 Ceramic layer and process method thereof. Background technique [0002] At present, the cylinder body is made of aluminum alloy, which is light in weight and good in heat dissipation, but its hardness is low. If the inner surface is not treated, it cannot be used normally. In order to make the inner surface of the cylinder have higher wear resistance, cast iron cylinder liners are generally used as inner linings, or electroplated chromium or (Ni-P)-SiC plating and other coatings on the inner surface of the cylinder. The former requires high processing technology and will increase the weight of the engine, while the latter has complex processes, high cost, and significant pollution to the environment. In addition, neither the cast iro...

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Problems solved by technology

The former requires high processing technology and will increase the weight of the engine, while the latter has complex processes, high cost, and significant pollution to the environment

In addition, neither the cast iron liner nor the electroplating composite coating can make the inner surface of the cylinder have good thermal insulation properties.

Chinese patent CN200310118909.9 reports a micro-arc oxidation treatment process for the inner surface of an aluminum alloy cylinder. This process can prepare a micro-arc oxidation ceramic layer with a uniform thickness on the inner wall of the cylinder, thereby improving wear resistance, corrosion resistance, and temperature characteristics, but the film layer is relatively thin, generally about 30 μm, and more importantly, it does not take into account that the thermal expansion coefficient of the ceramic layer is very different from that of aluminum. When the temperature changes, it will cause a large stress and cause the oxidized ceramic layer. At the same time, due to the good thermal insulation properties of the oxide ceramic layer, it is difficult for the heat generated by the gas in the cylinder to be exported through the wall of the cylinder, so that the working temperature of the piston ring and the piston is too high, and the size of the piston is too large to expand, resulting in "cylinder stuck". " or " pulling cylinder " phenomenon

Furthermore, if this process is used to prepare a thicker ceramic layer on the inner surface of the cylinder, a higher oxidation voltage is required, the energy consumption is high, and the requirements for the power supply are also higher.

Therefore, the above method is difficult to practical

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