The invention discloses a heat spraying-PVD composite coating and a preparing method thereof, and belongs to the technical field of surface coatings. The composite coating sequentially comprises a base body, a heat spraying coating and a PVD hard film from interior to exterior. The base body is a metal material base body and comprises an aluminum alloy, a titanium alloy and steel. The heat spraying coating is a heat spraying ceramic coating and comprises a WC-Co base ceramic coating, an NiCr-Cr3C2 base ceramic coating, an Al2O3 base ceramic coating and a ZrO2 base ceramic coating. The PVD hard film is made of metal nitride ceramics and comprises a CrN ceramic coating, a TiN ceramic coating, an AlCrN ceramic coating and an AlTiN ceramic coating. The heat spraying coating has high hardness, a powerful supporting function can be provided for the PVD coating, and the binding force of the composite coating film-base is improved. The PVD coating is high in hardness and is very dense, the PVD coating is deposited on the surface of the heat spraying coating, and gaps of the heat spraying coating are subjected to effective hole sealing. Thus, compared with the heat spraying coating or the PVD coating, the heat spraying-PVD composite coating has high coating bearing capability and abrasion resisting and corrosion resisting performance at the same time.

Heat spraying-PVD composite coating and preparing method thereof

The invention discloses a nano-ceramic composite spraying powder and a preparation method for the same. The nano-ceramic composite spraying powder comprises MCrAlTaY with definite components, nano-aluminium oxide and/or nano-yttrium oxide, and nano-titanium diboride, wherein in MCrAlTaY, M is Ni, Co or Ni-Co alloy; the MCrAlTaY and the nano-aluminium oxide and/or nano-yttrium oxide form an alloy oxide ceramic composite powder; and nano-titanium diboride is nano-metal ceramic powder. The preparation method comprises the following steps of: conveying the composite powder in a ball mill; adding a ball-milling medium and an organic adhesive; starting the ball mill and uniformly mixing; adding the ceramic powder; and starting the ball mill again until all the ceramic powder is uniformly wrapped on the particle surface of the composite powder, taking out the wet material and drying, and then obtaining the nano-ceramic composite spraying powder. The spraying powder is good in resistance to high-temperature oxidation and resistance to thermal corrosion, thus enhancing the toughness and the resistance to thermal fatigue strength of a coating; and the prepared powder is uniform and complete in coating shape and good in flowability, thus reducing spraying difficulty.

Nano-ceramic composite spraying powder and preparation method for same

The invention discloses a surface treatment method for loop back rolls of hot continuous rolling units, and the method comprises the following steps of: firstly, carrying out cleaning pretreatment on the surface of a loop back roll, and carrying out overlay welding on the surface of the loop back roll by using a hard-surface alloy welding wire so as to form a middle transition layer with the thickness of 2-3 mm, wherein the overlay welding current is 380-450A, the voltage is 26-30V, and the overlay welding speed is 300-400 mm/min; then, preparing a work coating with the thickness of 0.5-2 mm by using a spray welding remelting way, wherein the work coating is made of a Ni-based alloy powder material, the distance between a spray gun and the surface of a workpiece is 250 mm, the powder feeding speed is 50-150 g/min, and the gas pressures of acetylene and oxygen are respectively 0.1-0.3 MPa and0.1-0.5 MPa; and finally, carrying out remelting treatment on the work coating by using an oxyacetylene flame gun, wherein the flow rates of acetylene and oxygen are respectively 1 kg/cm and 4.5 kg/cm , and the remelting temperature is 800-1200 DEG C. The method disclosed by the invention can be used for improving the wear resistance and corrosion resistance of the surfaces of loop back rolls, prolonging the service lives of the loop back rolls, ensuring the normal operation of hot continuous rolling units, and improving the quality and production efficiency of strip steel rolling.

Surface treatment method for loop back rolls of hot continuous rolling units

The invention discloses a preparation method for a wear resistant and anti-bonding process roller surface composite layer. Specifically, the method includes: conducting cleaning and activation pretreatment on a process roller matrix surface; employing supersonic and other spraying equipment to prepare a thermal spray metal ceramic coating with thickness of 0.05-0.30mm on the process roller matrix surface; carrying out cleaning and activation pretreatment on the metal ceramic coating; and then preparing an Ni-P plating layer by chemical plating, and controlling the Ni content of the plating layer at 88-92%, the P content at 8-12%, and the thickness of the Ni-P plating layer at 0.01-0.03mm. The method reserves all excellent comprehensive performance of the process roller thermal spray coating, simultaneously improves the anti-bonding performance, prolongs the actual service life of the process roller, and ensures the quality of strip steel products.

Preparation method for wear resistant and anti-bonding process roller surface composite layer

The invention discloses a method for preparing a Ni-based alloy-TiB2 nano coating Powder is sprayed on a base material through supersonic speed flame so as to form a nano-structured coating, wherein the powder comprises two components, namely, 60-80 percent by weight of Ni-based alloy powder, and 20-40 percent by weight of TiB2 The nano coating prepared according to the technical scheme is dense in tissue and uniform in distribution, is of a certain flat layered distribution structure, and is not clear in boundary distribution amount spraying ions In addition, the prepared nano coating further contains special or elliptical unmelted or semi-melted grains, and due to such a structure, the prepared nano coating has higher bonding strength and better abrasion resistance Therefore, the comprehensive application property of the protection coating is improved, and the high-temperature corrosion resistance and the erosive wear resistance of 'four tubes' of a boiler are further improved

Method for preparing Ni-based alloy-TiB2 nano coating

The invention provides metal ceramic powders used for thermal spraying on a furnace roller surface. The metal ceramic powders, consisting of alloy powders and ceramic powders, comprise, by weight, 13-25% of Cr, 3-10% of Al, 0.1-1% of Y, less than 12% of Ta and balance being at least one of Co and Ni. The metal ceramic powders are characterized in that: the ceramic powders contain TiB2 and Al2O3, which account for, by weight, 15-25% of total weight of the metal ceramic powders. In the invention, anti-buildup performance and friction and wear resistance performance of thermal spray coatings made by the metal ceramic powders can be effectively improved. Excellent comprehensive properties can be maintained in harsh conditions of real production.

Metal ceramic powders used for thermal spraying on furnace roller surface

The invention discloses a method for preparing a work layer on the surface of a process roller of a cold rolling unit, which comprises the thermal spraying of a metal ceramic coating on the surface of the process roller. The method comprises the following steps: firstly, cleaning and activating a thermal spraying coating on the surface of the process roller; secondly, chemically plating a Ni-P layer, wherein chemical plating solution comprises 30g/l of nickel sulfate, 25g/l of sodium hypophosphite, 15ppm of activator, 5g/l of accelerator, 10g/l of lactic acid and 15g/l of citric acid; thirdly, immersing the process roller into the plating solution, wherein the temperature of the plating solution is between 80 and 100 DEG C, the nickel content is 88 to 92 percent, and the phosphorus content is 8 to 12 percent; and finally, when the thickness of the chemical plating layer reaches 0.01 to 0.02mm, stopping the chemical plating, performing thermal treatment at the temperature of between 50 and 450 DEG C, and preserving the heat for 0.5 to 5 hours. The work layer on the surface of the process roller prepared by the method has abrasion resistance, impact resistance, roughness retention capacity and excellent anti-adhesion performance, meets the operating requirement of long term and stability of the process roller, and prolongs the service life of the process roller.

Ju Yuan

Papers

Metal ceramic powders used for thermal spraying on furnace roller surface

Method for preparing work layer on surface of process roller of cold rolling unit