Thermal spraying - Determination of the deposition efficiency for thermal spraying
1Key Takeaways
This document specifies a test procedure to determine the deposition efficiency for thermal spraying. It provides a reliable comparison method between different spray processes and different feed stock. It is applicable for all thermal spray processes (see ISO 14917) and all wire, rod, cord and powder spray materials. …
2Expert Interpretation
This in-depth analysis of ISO 17836:2017, the international standard for determining thermal spray deposition efficiency, covers test procedures, calculation methods, and implementation key points. It compares the efficiency of different spray processes and provides standardized testing solutions for materials such as powders and wires, helping companies optimize their spray process parameter selection.
Interpretation of the Standard's Core Content
ISO 17836:2017 defines a method for determining the deposition efficiency (DE) of thermal spraying. The calculation formula is: ηD = (Δmtp/msm) × 100%, where Δmtp is the specimen mass difference and msm is the spray material feed. This standard applies to all thermal spray processes and materials such as wire, rod, and powder that meet the ISO 14917 definition.
Comparison of key test elements
| Test elements | Tubular specimen (A) | Plate specimen (B) |
|---|---|---|
| Dimensions | 150-170×200×3-5mm | 300×300×1mm |
| Spraying area | An edge area ≥1 spray beam width needs to be reserved | |
| Applicable scenarios | Rotating part simulation | Plane component simulation |
Technical Implementation Key Points
Case Study: When an aviation parts manufacturer used the HVOF process to spray WC-12Co powder, the DE value measured using this standard was 65% ± 2%. The test used a tubular specimen, maintained a 90° spray angle, controlled the spray gun's oscillation speed at 200 mm/s, and maintained a cooling system to maintain the specimen temperature below 150°C.
Key control parameters include:
- Feed rate accuracy must reach ±0.5g/min
- Spraying time benchmark 30 seconds (extendable)
- Mass measurement accuracy ≥0.1g
Standard Evolution Analysis
Main improvements compared to the 2004 version:
- Added a standardized scheme for plate specimens
- Clarified quantitative requirements for spray gun oscillation trajectory
- Strengthened data integrity specifications for test reports
Implementation Recommendations
1. Process Optimization: A comparison of DE values shows that the efficiency difference between plasma spray (PS) and high velocity oxygen fuel (HVOF) for the same material can reach 15-25%
2. Cost Control: For every 5% increase in DE value, the coating cost of typical aviation parts can be reduced by approximately 8-12%. 3. Data Recording: It is recommended to use the recording template in Appendix C of the standard, which must include at least 12 mandatory parameters.