Shopping Basket
PDF's from PIM International
Production of fine titanium powders via the Hydride-Dehydride (HDH) process
Feature article: PIM International, Vol.2 No. 2 June 2008, pages 55-57, 991 words
Reading Alloys Inc., An AMETEK Company, 220 Old West Penn Ave, Robesonia, PA 19551, USA
Introduction
Titanium powders have been used successfully in a wide range of near shape PM applications, and in recent years the demand for finer titanium powders for PIM applications has increased significantly. Dr Colin McCracken and Dan Barbis of Reading Alloys Inc. review the latest developments in the manufacture of finer titanium powders using the hydride-dehydride (HDH) process. They also review the impact of raw materials and particle size distribution on both the powder morphology and powder chemistry.
Reading Alloys Inc. (RAI) has been one of the leading producers of master alloys for over 50 years, and is well known in both the titanium and aerospace industries. Master alloys are typically supplied in the size range of 6.3mm to 300µm and are used, for example in the production of titanium alloys by providing aluminium, vanadium, tin, molybdenum, chromium, and iron alloying elements [1]. These titanium alloys exhibit both high strength and low density, which make them ideally suited for aerospace and other applications. Titanium and its alloys also exhibit other important characteristics, such as high corrosion resistance and very good biocompatibility, and are also used extensively in implantable medical applications [2-3].
The majority of high purity fine titanium powders used for powder injection moulding applications are produced by a gas atomisation process, which results in spherical powder particles with a narrow particle size distribution (PSD) range. This review will explore an alternative powder manufacturing process referred to as the Hydride-Dehydride (HDH) process. Unlike the gas atomisation process, which produces a near-final PSD, the HDH process is used to resize large titanium pieces down to a finer PSD through crushing, milling and screening. The resulting high purity, finer titanium powder can have a similar PSD to atomised powder, but a very different ......
Further sections of this article include:
- Manufacturing route
- Titanium powder morphology
- Titanium powder chemistry
- Summary
Figures and Tables:Fig.1 Flow diagram of the HDH process Fig. 2 RAI’s production HDH unit. Fig. 3 SEM image (x50) of coarse HDH Ti powder produced from wrought titanium feedstock screened to 212-300µm Fig. 4 SEM image (x100) of coarse HDH Ti powder produced from sodium reduced sponge powder screened to 212-300µm Fig. 5 SEM image (x100) of coarse HDH Ti powder produced from magnesium reduced sponge powder screened to 212-300µm Fig. 6 SEM image (x750) of coarse HDH Ti powder produced from wrought titanium feedstock screened to lt;25µm Fig. 7 SEM image (x750) of coarse HDH Ti powder produced from sodium reduced sponge powder screened to lt;25µm Fig. 8 SEM image (x500) of coarse HDH Ti powder produced from magnesium reduced sponge powder screened to lt;25µm Fig. 9 Typical Malvern (laser) PSD curves for different titanium raw materials Fig. 10 Typical Oxygen content as a function of PSD for Magnesium reduced Titanium sponge Table 1 Typical Chemistry for different lt;25µm Titanium raw materials. |
