Mild Operating Conditions
For sealing surface coatings of valves in clean water pipelines (alumina material): the medium is non-corrosive and free of solid particle erosion, with only low-pressure friction generated during opening and closing. The service life can reach 5–10 years or even longer.
Severe Operating Conditions
For coatings of slurry and mineral slurry valves (silicon carbide or WC-Cr₃C₂ composite coatings): the medium contains high-hardness particles flowing at high velocity, subjecting the coating to long-term erosive wear. Their typical service life ranges from 6 to 18 months. If the medium also carries strong acids or alkalis (e.g., corrosive chemical media), coating service life may be further reduced to 3–6 months.
High-Temperature Operating Conditions
For zirconia thermal barrier coatings on high-temperature flue gas butterfly valves operating continuously at 500–800°C: service life can hit 3–5 years without drastic temperature fluctuations. Frequent thermal cycling, however, readily triggers coating cracking and spalling due to thermal stress, cutting service life down to 1–2 years.
Impacts of Coating Materials and Fabrication Processes
Material Compatibility
Silicon carbide and tungsten carbide-based coatings are selected for wear-resistant service conditions, while titanium oxide and silicon nitride coatings apply to anti-corrosion scenarios. Mismatched materials directly halve service life. For instance, an alumina coating deployed against strong acid media may suffer pitting corrosion and spalling within 3 months.
Process Quality
High-velocity oxy-fuel (HVOF) spraying produces highly dense coatings with porosity below 1% and bonding strength exceeding 70 MPa, delivering a service life 2–3 times longer than conventional plasma-sprayed coatings. Laser cladding yields coatings with metallurgical bonding, which outperform thermal-sprayed counterparts in impact resistance and offer extended service life under alternating loads.
Role of Routine Maintenance
Regular removal of particulate contaminants inside valves, avoiding excessive valve cycling (to reduce friction on sealing surfaces), and maintaining medium temperature and pressure within design limits can effectively extend coating service life by 30%–50%. In contrast, rough operation or operation beyond rated working conditions accelerates coating wear and cracking.Mild Operating Conditions
For sealing surface coatings of valves in clean water pipelines (alumina material): the medium is non-corrosive and free of solid particle erosion, with only low-pressure friction generated during opening and closing. The service life can reach 5–10 years or even longer.
Severe Operating Conditions
For coatings of slurry and mineral slurry valves (silicon carbide or WC-Cr₃C₂ composite coatings): the medium contains high-hardness particles flowing at high velocity, subjecting the coating to long-term erosive wear. Their typical service life ranges from 6 to 18 months. If the medium also carries strong acids or alkalis (e.g., corrosive chemical media), coating service life may be further reduced to 3–6 months.
High-Temperature Operating Conditions
For zirconia thermal barrier coatings on high-temperature flue gas butterfly valves operating continuously at 500–800°C: service life can hit 3–5 years without drastic temperature fluctuations. Frequent thermal cycling, however, readily triggers coating cracking and spalling due to thermal stress, cutting service life down to 1–2 years.
Impacts of Coating Materials and Fabrication Processes
Material Compatibility
Silicon carbide and tungsten carbide-based coatings are selected for wear-resistant service conditions, while titanium oxide and silicon nitride coatings apply to anti-corrosion scenarios. Mismatched materials directly halve service life. For instance, an alumina coating deployed against strong acid media may suffer pitting corrosion and spalling within 3 months.
Process Quality
High-velocity oxy-fuel (HVOF) spraying produces highly dense coatings with porosity below 1% and bonding strength exceeding 70 MPa, delivering a service life 2–3 times longer than conventional plasma-sprayed coatings. Laser cladding yields coatings with metallurgical bonding, which outperform thermal-sprayed counterparts in impact resistance and offer extended service life under alternating loads.
Role of Routine Maintenance
Regular removal of particulate contaminants inside valves, avoiding excessive valve cycling (to reduce friction on sealing surfaces), and maintaining medium temperature and pressure within design limits can effectively extend coating service life by 30%–50%. In contrast, rough operation or operation beyond rated working conditions accelerates coating wear and cracking.
Manufactured with industrial resin system and ceramic fillers, zero VOC emission, compliant with EU RoHS standards.
Continuous operating temperature ≤ 200°C; short-term peak temperature up to 250°C.
Coating thickness ranges from 80 to 200 microns, adjustable per application requirements.
Impact test: A Φ20 mm steel ball dropped freely from a height of 1.5 m causes no cracking of the coating.
Salt spray test: No coating damage after 1000 hours of testing.
Control reference: After only 72 hours of salt spray test, floating rust forms on 304 stainless steel valve plates, and nickel-plated ductile iron surfaces are fully corroded.
Immersion test: The ceramic coating remains free of blistering, delamination and discoloration after 10 years of immersion in 10% sodium hydroxide solution and 10% sodium chloride solution respectively.
Simulation tests on 4-inch valve plates:
(1) Immersed in simulated seawater (3.5 wt% salt content) for 30 days; no coating degradation observed.
(2) The butterfly valve undergoes 200,000 continuous opening-closing cycles with no erosion or wear detected on the ceramic coating.
(3) Continuous flushing test for 240 hours under half-open position (1/20 opening) with impurity-laden simulated seawater (3.5 wt% salt content + 5 wt% 10-mesh silica powder); the coating stays intact without damage..
