Wear resistance of HVOF- and HVAF-sprayed (Ti,Mo)(C,N)–Ni coatings from an agglomerated and sintered powder

• (Ti,Mo)(C,N)-25 wt% Ni coatings obtained by spraying an agglomerated and sintered feedstock powder using different high velocity air-fuel (HVAF) and high velocity oxygen-fuel (HVOF) deposition processes are comparatively analysed for their sliding, abrasion and impact resistance. All HVOF-sprayed coatings are particularly dense, with ≈800 HV hardness (tested at 100 gf, 300 gf and 500 gf). In-flight oxidation resulted in some embrittlement, as revealed by scratch tests. In ball-on-disk sliding against an Al2O3 counterpart, they maintained a mild wear regime (wear rates ≤10−6 mm3/(N⋅m)) from room temperature up to 600 °C, with better performance in comparison to Cr3C2–NiCr reference coatings. At room temperature, the Ti(C,N) hard phase limited the abrasive cutting by counterbody asperities. At 400 °C and 600 °C, the coatings developed a thin, protective oxide tribofilm. They also exhibited no interface delamination in cyclic impact tests. However, they suffered higher wear (≈3–5 × 10−3 mm3/(N⋅m)) in high-stress particle abrasion testing, particularly when compared to HVAF-sprayed Cr3C2–NiCr. Gaining improved control over in-flight oxidation of (Ti,Mo)(C,N)–Ni during spraying is probably the key to overcome this limitation. The HVAF-sprayed (Ti,Mo)(C,N)–Ni coating exhibited severe interlamellar decohesion under all test conditions, as the limited melting degree of the feedstock did not compensate for the intrinsic microstructural inhomogeneity of the powder particles. 

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

Keyword

Abrasion

Hardmetals

High velocity air-fuel (HVAF)

High velocity oxygen-fuel (HVOF)

Sliding wear

Titanium carbonitride

Agglomeration

Air

Alumina

Aluminum oxide

Erosion

Feedstocks

HVOF thermal spraying

Oxygen

Sintering

Sprayed coatings

Titanium compounds

Velocity

Velocity control

Wear resistance

Agglomerated powders

Hard metals

High velocity air fuels

High velocity air-fuel

High velocity oxygen fuels

High velocity oxygen-fuel

In-flight oxidation

Ni coating

Titanium carbonitrides

Publication and Content Type

ref (subject category)

art (subject category)