Thixotropic properties of multi-functional binder and compaction behaviour of the low alloyed binder-treated powder

ABSTRACT

A new multi-functional binder with adhesive and lubricant effect was designed, and the thixotropic properties of the binder components and the resulting binder, the adhesive effect and compaction behaviour of the binder-treated powder were investigated. The results demonstrate that the thixotropic components in the binder are polyethylene wax and microcrystalline wax. With the increase of polyethylene wax content, the critical solid–liquid shear stress of binders decreases gradually. The main lubrication components in the low-pressure and high-pressure stages during the compaction process are found to be polyethylene wax and microcrystalline wax, respectively. The fine metal or graphite additives are effectively bonded on the surface of iron particles and filled in the pits. The green density reaches 7.25 g cm⁻³ at 600 MPa when the content of polyethylene wax is 30%. From 400 to 750 MPa, the content of polyethylene wax corresponding to the minimum ejection pressure decreases from 20 to 0%.

KEYWORDS:

• Iron-based powder metallurgy
• binder-treated powder
• thixotropic property
• shear stress
• green density
• ejection pressure
• adhesion effect

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Yan Chen is a doctoral candidate.

Lin Zhang is a professor. His research interest includes oxide dispersion strengthened alloy and PM superalloys.

Haishen Sun is a doctoral candidate.

Fangfang Chen is a master graduate.

Xuanhui Qu is a professor. His research interest is advanced powder metallurgy technologies and materials.

Additional information

Funding

This work is financially supported by National Natural Science Foundation of China (51574030, 51574029) and National Key R&D Program of China (2017YFB0305600, 2016YFB0301400).