奈米材料(Nanomaterials)

Electronless nickel-phosphorous coatings are used widely in many of the industrial applications because the unique properties, including of high wear resistant, high corrosion resistant, highly hard and tough property, and good lubrication. By combining nano–sized particles as a reinforcing phase inside of the Ni-P matrix to obtain functional nanometer composite coating with electronless co-deposition process, the properties of Ni-P coating are to be mainly improved and sometimes new features are fully added to the coating performance. For this purpose, different nanoparticles like nano-SiC, WC, Al2O3, TiO2, and ZnO as harder particles and PTFE, MoS2 and graphite as lubrication particles are added for the coatings. Out of these nanoparticles, PTFE has got tremendous interest by its properties like a lower friction coefficient, good for nonstick surfaces and dry lubricity, anti-fouling properties, and very good wear and corrosion resistant. Ni-P-PTFE can be used as an anti-sticking coating. Condensed fluorine atom in these molecules at the outer layer are the main cause of the physical properties of PTFE like its low surface energy and very lower friction coefficient. By codeposition of PTFE in the matrix of the coating, the properties of Ni-P and PTFE can be used simultaneously. PTFE has excellent anti-stick properties due to the low surface energy of PTFE polymer (18.6 mN/m). Therefore another potential application of Ni-P-PTFE is the reduction for fouling. For example, the formation of limestone with the surfaces of heat-exchange exchangers or heat-exchange elements is a serious problem. The sediments are one of the natures problems on the designation and operation of many production equipments and processes. Unasked for sediments can affect the equipment in two ways are:

• The lower thermal conductivity of the formed sediments can increase resistance for heat transfer, and therefore reduces the efficiency of heat-exchanging exchangers.
• Fouling the ducts reduces the cross-section area of the fluid path and the friction becomes higher, causing to an increase of pressure drop across the system.

Any methods for reducing sediments can decrease costs. It was found that the adhesion of the formed sediments on the surfaces with low surface energy is poor. For this purpose, many polymeric coatings have been used. The lower thermal conductivity, low wear resistance and poor adhesion of the substrate of the polymer coatings have limited their industrial applications. Since Ni-P-PTFE coating is metallic based composite, its thermal conductivity, mechanical strength, and wear-resistant properties are much bigger than PTFE coatings, while it has a low friction coefficient and less surface energy.

Electronless 1Electroless nickel-phosphorous coatings are used widely in many of the industrial applications because the unique properties, including of high wear resistant, high corrosion resistant, highly hard and tough property, and good lubrication. By combining nano–sized particles as a reinforcing phase inside of the Ni-P matrix to obtain, a functional nanometer composite coating with electronless co-depositionis produced by an electroless codeposition process, the . The combined properties of the Ni-P coating are to be mainly improved and sometimessome new features are fully 2added to the coating performance. For this purpose, differentinstance, nanoparticles likesuch as nano-SiC, WC, Al₂O₃, TiO₂, and ZnO as harder particlesincrease hardness in the coatings, and nanoparticles such as PTFE, MoS₂, and graphite asincrease lubrication particles are added for the coatings. Out. out of these nanoparticles, PTFE has got tremendous interest bydue to its properties like a, including low surface energy and3 lower friction coefficient, good for nonstick surfaces and dry lubricity, lubricants, anti-fouling properties, and very good wear and corrosion resistantresistance. Ni-P-PTFE can be used as an anti-sticking coating. Condensed fluorine atom in these molecules at the outer layer are the main cause of the physical properties of PTFE like its low surface energy and very lower friction coefficient. By codeposition of PTFE in the matrix of the coating, the properties of Ni-P and PTFE can be used simultaneously. PTFE has excellent anti-stick properties due to the low surface energy of PTFE polymer (18.6 mN/m). Therefore another potential application of Ni-P-PTFE is the reduction for fouling. For example, the formation of deposits resembling 4limestone with the surfaces of heat-exchange exchangers or heat-exchange elements is a serious problem. The sediments are one of the natures problems on the designationdesign and operation of many production equipmentsequipment and processes. Unasked for These unwanted sediments can affect the equipment in two ways are:

• The lower thermal conductivity of the formed sediments can increase resistance for heat transfer, and therefore reduces the efficiency of heat-exchanging exchangers.
• Fouling the ducts reduces the cross-sectionsectional area of the fluid path and the friction becomes higher, causing to an increase of pressure drop across the system.

Any methodsMethods5 for reducing sediments such sedimentary build-up can decrease costscost. It was found that the adhesion of the formed sediments on the surfaces with low surface energy is poor. For this purposeTherefore, many polymeric coatings have been used. The lower thermal conductivity, low wear resistance and poor adhesion of the substrate of the conventional polymer coatings have limited their industrial applications. Since Ni-P-PTFE coating is a metallic based composite, its thermal conductivity, mechanical strength, and wear-resistant properties are much bigger than PTFE coatings, while it has a low friction coefficient and less surface energy.

Electronless1Electroless nickel-phosphorous coatings are used widely 2used in many of the industrial applications because theof their unique properties, including of high such as being highly wear resistant, high and, corrosion resistant, highly along with being very hard and tough property, and tough as well as a 3good lubrication. By combining nano–sized particles as a reinforcing phase inside of the Ni-P matrix4 to obtain, alubricant. A functional nanometer composite coating with electronless co-depositionis produced by an electroless codeposition process, theco-deposition process that combinesi nano-sized particles as a reinforcing phase within a Ni-P matrix. The combined properties of the Ni-P coating are to be mainlygreatly improved and sometimessome new features are fully 5added to enhance the coating performance by adding different nanoparticles. For this purpose, differentinstance, nanoparticles likesuch as nano-SiC, WC, Al₂O₃, TiO₂, and ZnO as harder particlesincrease hardness in the coatings, and nanoparticles such as polytetrafluoroethylene (PTFE6), MoS₂, and graphite asincrease lubrication particles are added for the coatings. Out. out of. Of these nanoparticles, PTFE has gotgarnered tremendous interest bydue to its properties like a, including low such as low surface energy and7 lowerlow friction coefficient, (good for nonstick surfaces and dry lubricity, lubricants,), anti-fouling properties, and very good wear and corrosion resistantresistance. Ni-P-PTFE can be used as an anti-sticking coating. Condensedstick coatings. The condensed fluorine atomatoms in these molecules at the outer layer are the main causesource of the physical properties of PTFE like itssuch as low surface energy (18.6 mN/m) and very lower friction coefficient. By codeposition, both excellent properties for anti-stick coatings. By co-deposition of PTFE in the matrix of the coating, the properties of both Ni-P and PTFE can be used simultaneously. PTFE has excellent anti-stick properties due to the low surface energy of PTFE polymer (18.6 mN/m). Therefore another 8The potential application of a Ni-P-PTFE iscomposite to the reduction for fouling. For example, the is foreseen as a potential solution to the serious problem of the formation of deposits resembling 9limestone withon the surfaces of heat-exchange exchangers or heat-exchange elements is a serious problem. The. These sediments are one of the naturesinherent problems onin the designationdesign and operation of many types of production and processing equipmentsequipment and processes8. Unasked for These unwanted sediments can affect the equipment in two ways are:: 10

• The lower thermal conductivity of the formeddeposited sediments can increase resistance for heat transfer, and therefore reduces resistance, thereby reducing the efficiency of heat-exchanging exchangers exchanger efficiency11.
• Fouling the ducts reduces the cross-sectionsectional area of the fluid path and the friction becomes higher, causing to an increase ofincreased friction and a pressure drop increase across the system.

Any methodsMethods for reducing sediments such sedimentary build-up 12can decrease costscost. It wasWe found that the adhesion of the formedsuch sediments on the surfaces with low surface energy is poor. For this purposeTherefore, many polymeric coatings have been used. The lowerLower thermal conductivity, low and wear resistance andas well as poor adhesion ofto the substrate of the conventional polymer coatings have limited their industrial applications. Since Ni-P-PTFE coating is based on a metallic based composite, its thermal conductivity, mechanical strength, and wear-resistant properties are much biggerbetter than PTFE coatings, whileand it also has a low friction coefficient and lessas well as low surface energy.