Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
  • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
  • B22F9/20—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B34/00—Obtaining refractory metals
  • C22B34/10—Obtaining titanium, zirconium or hafnium
  • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
  • C22B34/1263—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction
  • C22B34/1277—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction using other metals, e.g. Al, Si, Mn
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B34/00—Obtaining refractory metals
  • C22B34/10—Obtaining titanium, zirconium or hafnium
  • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
  • C22B34/1263—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction
  • C22B34/1286—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction using hydrogen containing agents, e.g. H2, CaH2, hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/04—Dry methods smelting of sulfides or formation of mattes by aluminium, other metals or silicon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/18—Reducing step-by-step
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/045—Alloys based on refractory metals
  • C22C1/0458—Alloys based on titanium, zirconium or hafnium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/05—Mixtures of metal powder with non-metallic powder
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C14/00—Alloys based on titanium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
  • B22F2009/041—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by mechanical alloying, e.g. blending, milling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2301/00—Metallic composition of the powder or its coating
  • B22F2301/20—Refractory metals
  • B22F2301/205—Titanium, zirconium or hafnium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

• the invention relates to a method for the production of metal alloy powders, in particular the invention relates to a method for the production of titanium alloy powders from titanium oxide starting materials.
• Metal alloy powders such as titanium alloy powders have both mechanical and corrosion resistance properties and can be used as structural materials in many industrial areas. Such areas include aerospace, automotive industries, chemical engineering industries, and even military hardware applications. This usefulness is primarily due to the characteristics of metal alloy powders such as their weight to strength ratio, oxidation resistance, and wear resistance amongst other characteristics. As a result, production of metal alloy powder, in particular titanium alloy powders, is always under constant investigation.
• titanium aluminides have been used as structural materials, coatings, and forming and near net shapes by applying powder metallurgy technology.
• titanium is the fourth most abundant metal in the earth's crust (0.86% by weight) behind aluminium, iron and magnesium, titanium alloys are not particularly widely used primarily due to the cost of processing the material. Similarly for the production of other metals and metal alloys, the cost and processing requirements are prohibitive.
• the invention provides a process for the manufacture of titanium alloy powders, the method including the following steps:
• step (e) crushing and washing the result of step (d); and (T) recovering the titanium alloy powder.
• step (b) is carried out at a temperature of between about 900 0 C and about 1100°C.
• step (d) is carried out at a temperature of between about 1100°C and about 1300°C.
• step (a) includes titanium dioxide and another metal oxide compound; and the titanium alloy powder recovered in step (T) is a titanium based metal alloy powder.
• step (a) is carried out for a time of between about one and about 10 hours; and more preferably step (a) is carried out for a time of between about one and about four hours.
• step (a) includes titanium dioxide and at least one other metal oxide or at least one non-metal oxide.
• the other metal or non-metal oxide is selected from any one or more of Ni 1 V 1 Co 1 Nb, Cr 1 Mo, Y,or Si oxide.
• the alloy powder produced is a Ti-Al-Ni 1 Ti-Al-V, Ti-Al-Co 1 Ti-Al-Nb, Ti-Al-Cr, Ti-Al- Mo, Ti-Al-Y or a Ti-Al-Si alloy.
• the non-metal oxide is SiO 2 and the product of step (f) is a Ti-Al-Si alloy.
• step (a) is carried out in a vacuum or an inert environment.
• step (a) combines TiO 2 and Al powders; the product of step (d) is a mixture of Ti-Al and soluble compounds; and a Ti-Al alloy is recovered in step (f).
• step (c) is also carried out in a vacuum or an inert environment.
• step (b) is carried out in an inert environment and steps (c), and (d) are carried out in the same inert environment.
• the inert environment in steps (a), (b), (c), and (d) is an argon environment.
• step (b) is carried out for at least about ten minutes; more preferably between about one and about two hours.
• step (d) is carried out for between about two and about eight hours; more preferably between about two and about four hours.
• the suitable reducing agent used in step (d) is calcium or magnesium hydride; most preferably calcium hydride.
• the crushing steps in steps (c) and (e) is carried out for a time of between about ten minutes and about one hour using a mechanical milling machine such as a ball or discus milling machine.
• the washing step in step (e) is a multi-step process using deionised water and a weak organic acid, for example acetic acid, in deionised water.
• a weak organic acid for example acetic acid
• the invention provides a titanium alloy powder when produced by a process of the first aspect of the invention.
• the invention provides a powder when produced by step (b) as an intermediate product for use in the process of the first aspect of the invention.
• the invention provides a process for the manufacture of titanium aluminide powder, the method including the following steps:
• step (b) is carried out at a temperature of between about 900°C and about 1100 0 C.
• step (d) is carried out at a temperature of between about 1100 0 C and about 1300°C.
• the invention provides a process for the manufacture of titanium alloy powders, the method including the following steps:
• step (c) 1500 0 C in a vacuum or an inert environment to reduce the oxide components of the titanium metal matrix ceramic composite; (d) crushing and washing the result of step (c); and
• the blended mixture in step (a) is blended by mechanical milling or low energy mixing techniques.
• the invention provides a titanium alloy powder when produced by a process according to the fourth or fifth aspect of the invention.
• the invention provides a titanium metal matrix ceramic composite powder when produced by step (b) as an intermediate product for use in the process of the first, fourth or fifth aspect of the invention.
• the invention provides a process for the manufacture of titanium alloy powders, the method including the following steps:
• step (e) crushing and washing the result of step (d);
• Preferably blending includes mechanical milling or low energy mixing techniques.
• the invention provides a titanium alloy powder when produced by a process according to the eighth aspect of the invention.
• Figure 1 shows the XRD pattern of the as-milled AI/TiO 2 powder produced by high- energy mechanical milling for 1 hour using the discus mill.
• Figure 2 shows a SEM micrograph of the cross section of the powder particles of the as-milled powder.
• Figure 3 shows the XRD pattern of the Ti(AI, O)/AI 2 O 3 composite powder produced by heat treating the AI/TiO 2 composite powder for 2 hours at 1000 0 C.
• Figure 4 shows a typical SEM backscattered micrograph of a Ti(AI,O)/AI 2 O 3 powder particle.
• Figure 5 shows the EDX spectra from different zones in a Ti(AI, O)/AI 2 O 3 composite powder particle (a) Ti(AI 1 O) phase and (b) AI 2 O 3 phase.
• Figure 6 (a) shows the particle morphology of the fine Ti(AI,O)/AI 2 O 3 powder, and (b) particle size distribution.
• Figure 7 shows the XRD pattern of the final Ti-Al powder after reduction, crushing and washing.
• Figure 8 shows the Ti-Al particle morphology of the powder after processing followed by reduction reaction and washing.
• Figure 9 shows the XRD pattern of the as-milled powder in the production of Ti-Al-V.
• Figure 10 shows the XRD pattern of the heat treated powder, at 1200 0 C for 4hrs in a horizontal tube furnace under argon gas protection to produce Ti-Al-V.
• Figure 11 shows the XRD pattern of Ti-Al after heat treatment in a pre-test example.
• Figure 12 (a) shows the EDX spectrum of Ti-Al-V powder and (b) the SEM micrograph of dried, but not finally crushed Ti-Al-V powder particles.
• Figure 13 shows the XRD pattern of the final T ⁇ -6AI-4V product powder after crushing and washing.
• Figure 14 shows the XRD pattern comparison between a standard T ⁇ -6AI-4V powder and the Ti-6AI-4V powder produced using a process of this invention.
• Figure 15 shows the XRD pattern of the final Ti-Al-Cr powder product after reduction reaction, crushing and washing.
• Figure 16 (a) shows the EDX spectrum of Ti-Al-Cr; (b) and a SEM micrograph of the cross-section of Ti-Al-Cr particles.
• Figure 17 shows the XRD pattern of the final Ti-Al-Y powder product after reduction, crushing and washing.
• Figure 18 a) shows the EDX spectrum of the final Ti-Al-Y powder after reduction, crushing and washing and b) a SEM micrograph of cross-section of a typical Ti-Al-Y particle.
• This invention relates to a process for producing titanium metal alloys from titanium oxide (i.e. TiO 2 ) and aluminium. If titanium dioxide and aluminium only are used as the starting materials then the result is a Ti-Al alloy.
• the process can also include the use of one or more other oxides (metal or non-metal).
• This other oxide material can be selected from oxides of Ni 1 V 1 Co, Nb, Cr 1 Mo, Y, Si, or other similar oxides.
• the result is at least a Ti-Al alloy powder. If another metal oxide is used the result is a Ti-ternary alloy powder. If SiO 2 is used the result is a Ti-Al-Si alloy.
• the present Applicant disclosed that by heating a Ti x Al y /AI 2 O 3 bulk composite, for example, to a temperature range of between about 1500 0 C and about 1650 0 C and holding at the temperature for a set period of time, ranging from about 0.5 to about 10 hours, at least the AI 2 O 3 particles were significantly coarsened.
• the material produced was more favourable for later separation steps. This was considered contrary to conventional wisdom as the coarsening of the embedded particles within a composite is usually undesirable, as coarsened particles can decrease the overall strength of the final product.
• the composite with the coarsened AI 2 O 3 particles was then crushed and milled to produce a Ti x AIy(OVAI 2 O 3 powder from which the coarsened material could be separated.
• Ti x AIy(O) rich powder having a volume fraction Of AI 2 O 3 preferably less than about 15% can be further reduced by mixing with calcium, calcium hydride or other reductants. This is then heated to facilitate the reaction of the AI 2 O 3 and to reduce the dissolved oxygen content in the Ti x AIy(O) phase.
• the present Applicant has now found that the coarsening and separation steps required by the process disclosed in PCT/NZ2003/00159 can be avoided, with the process still providing high-quality metal alloy powder materials, using a suitable reducing agent, such as calcium or magnesium hydride, in the process. Further, the Applicant has also found that this process, absent the coarsening and separation steps, also allows the inclusion of other oxides with the TiO 2 together with aluminium. This use of multiple oxides has the advantage that the process can produce multiple metal (or metal/non-metal) alloy powder, which includes titanium.
• Calcium hydride is the preferred suitable reducing agent as, following its use as a reductant material, the resultant "waste" calcium oxide product of the reduction step is soluble and can be washed out with water.
• CaH 2 is also readily available and relatively easy to handle. MgH 2 is also an option but is more difficult to handle and the dissolvable products resulting from its use are less environmentally acceptable, and thus MgH 2 is less preferred.
• the solubility of the resultant product of the use of the suitable reducing agent is important as it allows the alloy powder produced not to be detrimentally affected by reaction with the resulting product of the reduction step.
• Other suitable reducing agents that also have the ability to produce a soluble product could also be used in this process. Reference to "suitable reducing agent" in this specification should be taken to refer to a reducing agent having these qualities.
• the first step of the process according to the present invention involves mechanically milling titanium dioxide, optionally with one or more other oxides, together with aluminium powder. These components form the charge powders to be placed inside the milling apparatus.
• the optional other oxide can be selected from any one or more oxides of Ni 1 V 1 Co, Nb 1 Cr 1 Mo 1 Y, or similar or non-metals such as Si, for example.
• the milling may involve using high energy discus milling apparatus.
• the components (TiO 2 , optionally one ore more other oxides, and Al powder) are placed within the milling apparatus and the process is continued until a powder having the desired particle characteristics is attained. Normally, it is anticipated that the given period will be in the range of about one to about ten hours, although this will depend upon the actual parameters of the system and choices made by the user. For example, use of a high energy discus mill may allow shorter times (e.g. one to about four hours) while ball mills may require longer times (e.g. seven to about ten hours). Typically, at the end of the milling process there will be a blended powder including fine fragments and a mixture of fine phases. The amount of the starting components used is based on the desired stoichiometric ratio of the product. For example, a small amount of an additional metal oxide (eg Y, Ni, Cr, Mo oxide etc) could be included to improve the quality of Ti alloys for various applications, such as coating applications.
• an additional metal oxide eg Y, Ni, Cr,
• the milling process is performed under an atmosphere inert to the components.
• the preferred gas being argon, however, other suitable gases of use with Ti processing known to the skilled person could also be used.
• a vacuum environment could also be used if desired.
• the initial milling step could be optionally part of the process of the invention as the milled product could be separately provided for use in the remaining steps.
• step (a) requires the blending of the titanium dioxide, optionally with one or more other oxides, together with aluminium powder.
• "Blending" according to the present invention includes any known blending technique. This includes, amongst other techniques, low energy mixing. Similar techniques as would be used in the mixing process of step (d) could be used. Blending will also include within its scope mechanical milling, such as described in connection with step (a) as discussed earlier. The remaining steps of the process according to this alternative embodiment are not altered. Following milling (or other blending techniques), the powder mixture is heated to a temperature of between about 700 0 C and 1200 0 C, preferably also in a vacuum or an inert environment, to form a titanium metal matrix ceramic composite (step (b)).
• This heating step can also be carried out in an inert or vacuum environment.
• This heating step can be carried out in a chamber or tube furnace and should be carried out for at least ten minutes, more preferably for between about one and two hours.
• the furnace should be capable of retaining the inert or vacuum environment.
• the titanium metal matrix ceramic composite formed from the heating step is then crushed to a powder form (step (c)).
• the crushing step can be carried out by using any known standard devices. Preferably, a ball mill with controllable speed or a discus mill is used. The time selected should be such that the particle size produced is suitable for the further processing desired (e.g. powder metallurgy, coatings etc.).
• the crushed metal matrix ceramic composite is then mixed with a suitable reducing agent, such as calcium or magnesium hydride, and heated to a temperature between about 1100 0 C and 1500 0 C in a vacuum or an inert environment (step (d)). It is more preferred to use a temperature of between about 1100°C and 1300 0 C.
• a suitable reducing agent such as calcium or magnesium hydride
• the amount of CaH 2 (or MgH 2 ) will be included according to stoichiometric ratio requirements.
• Mixing can be carried out by any suitable low energy technique that results in a blending of the components.
• the environment is preferably of the same type as used for the milling process. This heating step can again be carried out in a furnace such as a chamber or tube furnace for at least about one hour and preferably and between about two and four hours.
• This heating step using the suitable reducing agent results in chemical reduction of the oxide component of the titanium metal matrix ceramic composite and the formation of a titanium based alloy plus calcium oxide and other soluble compounds.
• the calcium oxide and other soluble products are then washed from the alloy, as discussed below.
• the use of calcium hydride as the reducing agent has the particular advantage of the resultant product of the reduction step being a soluble calcium oxide which can then be washed from the desired product.
• a similar reduction result would be achieved by using MgH 2 , but the "waste" soluble product (MgO) is less environmentally acceptable.
• the crushing process after the reduction step is preferably carried out using a ball mill or discus mill or similar device.
• the crushing time selected should be sufficient to result in a particle size suitable for washing and allowing the release of the impurities (e.g. CaO) from the crushed powder.
• deionised water should preferably be used to reduce the presence of harmful ions.
• the washing process should be repeated, and include washing with deionised water followed by decanting of the water from the powder. This is followed by final washing with a weak organic acid solution, such as acetic acid in deionised water (preferably less than about 15wt% acid concentration).
• the desired titanium alloy powder is then collected (step (T)) by known means.
• the intermediate titanium metal ceramic composite could be completed separately to the reduction and the final alloy recovery steps.
• the composite powder could be stored, possibly transported, and undergo the reduction step later, possibly at another site.
• the milled intermediate product could be stored, and possibly transported, for heat treatment at a later place or time.
• Such a temporally split process is also intended to be included within the scope of this invention.
• the milled Ti oxide (and optionally one or more other oxides) plus Al, and/or the titanium metal matrix composite material, as intermediates in the process of this invention may also be another aspect of this invention.
• the metal alloy powder product which is produced by the process according to the present invention, will depend upon the charge powders which are used in the initial milling step (i.e. step (a)).
• the charge powders will include titanium dioxide and - aluminium powder, optionally together with one or more other oxides.
• High quality Ti-Al can be produced, as can Ti ternary metal/non-metal alloys such as Ti-Al-V; Ti-Al-Nb, Ti-Al-Co, Ti- Al-Cr, Ti-Al-Y, Ti-Al-Mo, Ti-Al-Ni and Ti-Al-Si alloys.
• Ti-Al-V Ti-Al-V
• Ti-Al-Nb Ti-Al-Co
• Ti- Al-Cr Ti-Al-Y
• Ti-Al-Mo Ti-Al-Ni
• Ti-Al-Si alloys Ti-Al-Si alloys.
• the amount of the suitable reducing agent (e.g. CaH 2 ) was calculated from the stoichiometric ratios used for the selected chemical reaction. Such matters would be well within the knowledge of a skilled person in this field.
• Figure 1 shows the XRD pattern of the as-milled AI/TiO 2 powder produced by high-energy mechanical milling for 1 hour using the discus mill.
• the XRD pattern shows TiO 2 and Al as the only existing phases. From this it may be concluded that there was no significant reaction between the phases during mechanical milling.
• Figure 2 shows a Scanning Electron Microscopy (SEM) micrograph of the cross section of the powder particles of the as-milled powder.
• the powder particles exhibit composite structure consisting Of TiO 2 particles (the dark phase) embedded in elongated Al particles (the bright phase).
• DTA Differential Thermal Analysis
• Figure 3 shows the XRD pattern of the Ti(AI, O)/AI 2 O 3 composite powder produced by heat treating the AI/TiO 2 composite powder for 2 hours at 1000 0 C under argon gas protection.
• the XRD pattern reveals Ti(AI 1 O) and AI 2 O 3 as the major phase. This confirms that heat treating the AI/TiO 2 composite powder for 2hrs at between about 700 0 C -1200°C is sufficient to turn the AI/TiO 2 composite powder into a Ti(AI,O)/AI 2 O 3 composite powder.
• the microstructure of the Ti(AI, O)/AI 2 O 3 composite powder particles was examined using Scanning Electron Microscopy (SEM).
• Figure 4 shows a typical SEM backscattered micrograph of a cross section of a Ti(AI,O)/AI 2 O 3 powder particle.
• the SEM examination showed that the AI 2 O 3 particles were uniformly distributed in the Ti(AI 1 O) matrix.
• the bright phase is Ti(AI 1 O) and the dark phase is AI 2 O 3 .
• the compositions of the different phases in the composite material were investigated using SEM and EDX technology.
• the EDX spectrum of the Ti(AI 1 O) matrix ( Figure 5(a)) shows Ti and Al peaks as major peaks and the O peak as a minor peak. This confirms that the matrix is a Ti rich phase, which contains a substantial amount of dissolved Al and O.
• the EDX spectrum of the AI 2 O 3 particles ( Figure 5(b)) revealed only Al and O peaks confirming that they are AI 2 O 3 phase.
• the spectrum also shows a weak Pt peak which is caused by the coating material applied to the resin mounted sample, and a weak Ti peak which is likely to be caused by signals from the surrounding matrix material.
• Figures 6(a) and (b) show the particle morphology (6(a)) and particle size distribution (6(b)) of the Ti(AI, O)/AI 2 O 3 powder produced after mechanical milling (crushing) of the Ti(AI, O)/AI 2 O 3 composite powder for 10min using a discus mill. All the particles are equiaxed.
• the particle size distribution curve of the powder shows two overlapping peaks in the range of 0.08-10 micron.
• Reduction was followed by crushing (in a discus mill) of the reduction product in order to increase the surface area of the powder particles.
• the crushing process can be performed using mechanical milling equipment for a period of time of preferably between IOmins to 1hour. The time used in this particular example was 30mins. This increases the efficiency of the following washing process to remove resulting soluble end products. Washing was multi- step using deionised water followed by a weak solution of acetic acid in deionised water (10wt% acetic acid). The final analysis results, following the operation of crushing, washing and drying out the final powder product, are shown.
• the XRD pattern of the final Ti-Al powder after reduction, crushing and washing is shown in Figure 7.
• the XRD pattern shows a single phase of Ti-Al alloy and no unwashed residual phases.
• the powder particle sizes are as shown in the following table - Table 1 :
• Table 1 shows the presence of fine particles of the Ti-Al final powder.
• Titanium dioxide Other metal single metal oxide (MO)
• the final products will be advanced titanium alloy powders with very fine particles at cost effective prices.
• These alloy powder could include as follows:
• a pre-test was carried out, this pre-test comprising mixing vanadium oxide, V 2 O 5 , together with TiO 2 , and Al. This mixture was prepared based on the stoichiometric ratio of [TiO 2 ,AI]:V of 98:2(wt%). The powder mixture was mechanically milled in a discus mill for 1hr. Milling was performed under argon gas protection.
• Figure 9 shows the XRD pattern of the as milled powder.
• the XRD pattern revealed TiO 2 , and Al as the main dominant phases and VO 2 as the minor phase. This indicates that no reaction occurred between TiO 2 , and Al phases and the only reaction occurring during milling was the reduction of the first form of vanadium oxide to its nearest oxide VO 2 .
• Figure 10 shows the XRD pattern of the heat treated powder, at 1200 0 C for 4hrs in a horizontal tube furnace under argon gas protection.
• the XRD pattern for the heat treated powder in Figure 10 exhibits AI 2 O 3 as the main dominant phase, the titanium rich phase as Ti 3 AI, and also the vanadium phases AIVO and VO as minor phases.
• Figure 12 shows the EDX spectrum of the final powder particles (following final crushing and washing).
• Figure 12(a) shows Ti, Al peaks as the major peaks, and a minor peak of V.
• the particle morphology is shown in Figure 12(b).
• the micrograph shows very fine agglomerated particles.
• Ti:AI:V 90:6:4 wt%
• the final Ti-Al-V particles were then studied.
• Figure 13 shows the XRD pattern of the final Ti-Al-V product powder.
• the XRD pattern shows a typical Ti-6AI-4V phase.
• Figure 14 shows a comparison of a Ti-6AI-4V standard commercially produced powder imported from China and the Ti-6AI-4V pattern of the powder produced following the process of this invention.
• Table 2 shows fine particles of the Ti-Al-V final powder were produced.
• the starting materials for this example were chromium oxide, titanium oxide and aluminium powders.
• a stoichiometric ratio of Cr 2 O 3 :TIO 2 :AI at 11.6:64.3:24.1 wt% was applied.
• the final powder was produced by following the steps of Example 2. This powder may be used for powder coating application.
• Figure 15 shows the XRD pattern of the final Ti-Al-Cr powder product after reduction, crushing and washing.
• the XRD pattern revealed Ti-Al as the dominant phase.
• Figure 16(a) shows the EDX spectrum of Ti-Al-Cr particles.
• Figure 16(b) shows a micrograph of a cross-section of Ti-Al-Cr particle.
• Table 3 shows that fine particles of the Ti-Al-Cr final powder were produced. Bigger sizes could be attributed to the particle agglomeration.
• Example 4
• the starting materials for this example were yttrium oxide, titanium oxide and aluminium powders. A stoichiometric ratio of Y 2 O 3 :TiO 2 :AI at 2:67.6:30.4 wt% was applied.
• the final powder produced by following the steps of Example 2 was Ti-Al-Y.
• the small amount of Y included is intended to improve the quality of the titanium alloy. This powder may also be produced for powder coating application.
• Fig. 17 shows the XRD pattern of the final Ti-Al-Y powder product after reduction, crushing and washing.
• the XRD pattern revealed Ti-Al as the dominant phase.
• Figure 18 (a) shows the EDX spectrum of the final Ti- Al-Y powder.
• the analysis shows Ti-Al peaks as the major peaks and Y as the minor peak (due to the small amount of Y 2 O 3 used in the starting material).
• An SEM micrograph of the final Ti-Al-Y powder after reduction, crushing and washing is shown in Figure 18(b). This shows the relatively large particle size of the Ti-Al-Y powder produced. This is also shown in Table 4 where the measurements of the particle size distribution are tabulated.
• Table 4 shows the particle sizes of the final Ti-Al-Y powder produced.
• Examples 2 to 4 show the successful production of a variety of multi-metal alloys including Ti and Al produced by the process of the present invention. Additional metals (eg V, Ni, Nb, Y, Cr, Co, Mo, etc) can be added to the alloy in different weight ratios as desired, including at low levels. Production of other multi-metal alloys based on Ti and Al will also be possible as would be apparent to a skilled person once in possession of this invention.
• Additional metals eg V, Ni, Nb, Y, Cr, Co, Mo, etc

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