Project's information
| Project's title | Research and manufacture a number of advanced inorganic coatings applied to civil and national defense |
| Project’s code | TĐVLTT.05/21-23 |
| Research hosting institution | Institute of Tropical Biology |
| Project leader’s name | Dr. Le Ba Thang |
| Project duration | 01/01/2021 - 31/12/2023 |
| Project’s budget | 8,000 million VND |
| Classify | Grade B |
| Goal and objectives of the project | - Successfully manufactured and mastered the technology of manufacturing multi-layer plating systems based on zinc and zinc-nickel alloy (eco-friendly KCl-based plating solution) with a stable process on a semi-industrial scale industry for civil and defense applications. |
| Main results | - Theoretical results: + The appropriate solution composition for the single-layer ZnNi alloy plating has been selected: KCl 170-230 g/l, NiCl2: 40 - 80 g/l, ZnCl2: 60 - 100 g/l. The resulting coating has a suitable alloy composition (10 - 15% Ni). + The appropriate plating regime has been determined: pH 2-5, temperature 20-35oC, current density 1-5 A/dm2, plating time 20-40 minutes... to produce plating layers with good quality, high protection and anti-corrosion ability for steel substrates. + Dispersed SiO2 nanoparticles, Al2O3 nanoparticles, and CeO2 nanoparticles into the plating solution and investigated the particle size distribution, measuring the zeta potential in plating solutions containing nanoparticles. Successfully introduced SiO2 nanoparticles, Al2O3 nanoparticles, and CeO2 nanoparticles into the coating layer. The influence of the concentration of SiO2 nanoparticles, Al2O3 nanoparticles, and CeO2 nanoparticles on the coating morphology, Tafel polarization curve, open circuit potential, and coating composition has been studied. SiO2 nanoparticles were selected for use in the ZnNi-composite alloy plating solution. + Has prepared a solution for making conversion coatings on the ZnNi plating layer based on Cr(III) with the mass ratio of NH4HF2/Cr(III) from 2/5 to 4/5, the appropriate pH is in the range of 1.75-2.25. Salt spray test results for conversion coated samples were achieved over 312 hours (until white rust appeared). + The (ZnNi)n and (ZnNi-nanosilica)n multilayer coatings have been fabricated with n = 1 and n = 3, and the thickness of each layer in the multilayer coating combinations has been determined. + The influence of air-compressed pressure and distance from the nozzle to the sample surface on the surface roughness of the steel substrate has been studied, and a mathematical equation has been built to show the relationship between surface roughness Rz and air-compressed pressure P and abrasive spray distance L: Rz = -10.32 + 9.607P – 0.0456L with reliability of 96.33%. + The optimal mode for abrasive blasting to create roughness on the steel surface is found: air air-compressed pressure is 8 bar, and an abrasive blasting distance is 100 mm. + The influence of electric current intensity, compressed air pressure, and spray distance on the porosity and adhesion of the coating has been studied. Developed a mathematical equation to show the relationship between the porosity of the Al-Mg coating and the technological parameters as electric current, compressed air pressure, and spray distance: Porosity = 18.116 – 0.008033* I – 1.5717*P + 0.0022*L with reliability of 98.92%. A mathematical equation was built to show the relationship between the adhesion of the Al-Mg coating with the technological parameters as electric current, compressed air pressure, and spray distance: Adhesion = -1.53 + 0.01775*I + 2.710*P + 0.00267*L with reliability of 97.25%. + The optimal electric arc spraying mode has been found to produce an Al-Mg coating with low porosity and high adhesion: current intensity is 300 A, compressed air pressure is 5.5 bar and spray distance is 163 mm. The cross-sectional structure, elemental composition, phase composition, porosity, microhardness, and adhesion strength of the coatings were studied. + The protection and corrosion resistance of Al-Mg coatings were studied using electrochemical methods and salt spray tests. Al-Mg coating achieves salt spray durability of > 3000 hours, and corrosion resistance in dry-wet cycles reaches > 110 days. + Successfully researched and manufactured 01 dry-wet cyclic corrosion testing system and 01 dynamic corrosion-abrasion testing system. + Researched the effect of nano SiO2 and nano Al2O3 content on the properties of Al-Mg/epoxy-nanocomposite coating and selected the nano content and type for a good quality coating of 1% nano Al2O3. + Researched the anti-corrosion protection ability of Al-Mg/epoxy-nanocomposite coating using electrochemical methods and salt spray testing. Al-Mg/epoxy-nanocomposite coating achieves salt spray durability > 6000 hours and dynamic abrasion corrosion resistance > 2700 hours. + Tested exposure to marine atmosphere of Al-Mg and Al-Mg/epoxy-nanocomposite coating systems at Nha Trang and Quang Ninh test stations. After 12 months, the coatings still have good protection for steel substrates. - Applied results: + Four technological processes for manufacturing multi-layer coating system (ZnNi-nanosilica)3/TĐ Cr(III) have been built; Technological process for manufacturing multilayer (ZnNi)n/Zn-nanocomposite/TĐ Cr(III) coating system; Technological process of manufacturing Al-Mg alloy coating by electric arc spraying method; Technological process for manufacturing Al-Mg/epoxy-nanocomposite coating, and all have been accepted. + Four product standards have been developed for the multilayer coating system (ZnNi-nanosilica)3/TD Cr(III). Product standards for multilayer coating system (ZnNi)3/Zn-nanosilica/TĐ Cr (III); product standards for Al-Mg alloy coatings; product standards for Al-Mg/epoxy-nanocomposite coatings and all of them have been released by the Institute of Tropical Technology. + Published a useful solution "PROCESS FOR MANUFACTURING THREE-LAYER ZINC-NIKEN COATING FROM KCl-BASED PLATING SOLUTIONS ON CARBON STEEL SUBSTRATE". + Announced 1 Invention "Process for manufacturing aluminum magnesium alloy coating containing nano aluminum oxide to protect carbon steel against corrosion and carbon steel with anti-corrosion coating is created by this process". + Successfully manufactured and mastered the technology of manufacturing multi-layer plating systems based on zinc and zinc-nickel alloy (use environmentally friendly KCl base baths) with 02 technological processes for manufacturing multi-layer coating systems (ZnNi -nanosilica)3/TD Cr(III); Technological process for manufacturing multilayer (ZnNi)n/Zn-nanocomposite/TĐ Cr(III) coating system that operates reliably on a semi-industrial scale for civil and defense applications. + Successfully manufactured and mastered the technology of manufacturing highly durable coatings from Al-Mg alloy using the electric arc spraying method with two processes: "Technological process of manufacturing Al-Mg alloy coatings by electric arc spraying method" and "Technological process for manufacturing Al-Mg/epoxy-nanocomposite coating". |
| Products of the project | - Scientific papers in referred journals (list): |
| Recommendations | We request the Vietnam Academy of Science and Technology to support funding so we can continue implementing the pilot production project to perfect the component's products before commercializing the product. |
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