Erosion Resistant Coating
The combination of extreme hardness with enhanced toughness provides excellent protection against erosion at various impingement angles.
Hard but brittle materials suffer from high erosion rates at angles close to 90 degrees. Ductile and tough metals which lack hardness are eroded more quickly at lower impingement angles of 30 degrees due to ploughing and cutting effects. In practical applications it is often difficult to prevent particles in turbulent fluid or gas flows from bombarding surfaces from various impingement angles. The Hardide coating has shown consistently low erosion rates at different impingement angles due to the combination of hardness, toughness and compressive stresses.
Erosion resistance tests were performed in accordance with ASTM G76-95; velocity was 70m/sec and aluminium oxide (particle size 50 microns) was used as the erosive material. The graph below presents the test results and comparative results for other hard materials at various angles of impact. The Hardide coating erosion rate was 0.017 – 0.019 mm3/g which is significantly better than the erosion rate of the tested types of cemented carbide, white iron, hard chrome and chrome carbide weld overlay. The Hardide coating resists erosion by alumina particles at 70m/sec; three times better than steel and more than two times better than cemented carbide (hardmetal). Hardide coatings also significantly exceeded various currently used hard materials in a sand/water erosion test.
|Erosion by Alumina hard particles carried by gas jet at 70 m/sec|
|Angle of target °||Erosion Rate, mm3/g*1000|
|Hardide||Chrome Carbide Weld Overlay||White Iron||AR-500 Abrasion-resistant steel||WC cladding||Hard Chrome|
Erosion Resistance Test ASTM G76-95
Hardide-T Erosion Resistance Test
Erosion test conditions (by Southampton University RIfI):
- Erodent: angular sand 300 μm average grain size in water,
- slurry concentration of ~2.1% w/w.
- jet velocity: 24 m/s
- impingement angle: 90 degrees
- total test time: 120 minutes
Erosion Rates Measured:
- Hardide-T Erosion Rate: 1.38 mg per hour
- HVOF coating 85WC-10Co-4Cr: 5-15 mg per hour
- stainless steel: 171 mg per hour
Hardide-T erosion rate was measured:
- 7x lower as compared to the average value of HVOF 85WC-10Co-4Cr;
- 125x lower than stainless steel