KOMPOZYTY (COMPOSITES) 2(22)5 Blesław Frmanek 1, Bżena Szczucka-Lasta 3 Plitechnika Śląska, ul. Krasińskieg 8, 4-19 Katwice Lucjan Pająk 2 Uniwersytet Śląski, ul. Bankwa 12, 4-7 Katwice STRUCTURE OF POWDERS FROM Ni-Al SYSTEM AND THESE MODIFIED BY CERAMIC PHASES Micrstructure, mrphlgy and phase cmpsitin f pwders frm the Ni-Al system is characterised. Atmisatin methd f melted Ni-Al allys was applied fr the preparatin f the Ni 3Al pwders. Pwders f NiAl and Ni 2Al 3-NiAl phases and these mdified by ceramic phases were prepared in the prcess f self-prpagatin, high-temperature synthesis. The structure f NiAl-Al 2O 3 and NiAl-Al 2O 3-AlN cmpsite pwders was studied by light and scanning micrscpy as well as by X-ray diffractin methds. The selected pwders are destined fr thermal spraying f catings. STRUKTURA PROSZKÓW Z UKŁADU Ni-Al ORAZ ICH MODYFIKACJA FAZAMI CERAMICZNYMI Przedstawin wyniki badań składu fazweg i mrflgii wybranych prszków z układu Ni-Al. Mieszaniny prszków wyjściwych niklu i aluminium są substratami d wytwarzania materiałów kmpzytwych z fazami międzymetalicznymi z wykrzystaniem prcesów metalurgii prszków i dlewniczych (tab. 1). Prszki faz międzymetalicznych z układu NiAl wytwarzan metdą rzpylania lub samrzwijającej się syntezy wysktemperaturwej SHS. Dyfraktgramy syntezwanych prszków, analizwane metdą Traya, przedstawine na rysunkach 1-4 wykazują pełną zgdnść z kartami ASTM. Charakterystyczną mrflgię prszków NiAl 7-3 i NiAl 95-5, ujawniną na mikrskpie skaningwym, przedstawin na rysunkach 6 i 7. Skład chemiczny wybranych materiałów NiAl kreślny metdą EDX pdan w tabeli 2. Dyfraktgram kmpzytweg prszku zawierająceg fazy: NiAl, tlenków aluminium i żelaz raz aztek aluminium charakteryzuje prszek trzymany w prcesie SHS (rys. 5). Złżny skład fazwy prszku wskazuje na ptrzebę dpaswania parametrów technlgicznych prcesu wytwarzania kmpzytwych prszków zadanym składzie fazwym. Wytwarzane prszki są przeznaczne dla prcesu natryskiwania cieplneg pwłk. INTRODUCTION Intermetallic NiAl allys have ptential high temperature structural materials because f their attractive prperties such as lw density, high melting temperature, high thermal cnductivity, very gd idatin and ht crrsin resistance and gd mechanical prperties [1, 2]. Metallurgy f pwders cmpletes the funding methds f intermetallic phases prductin f nickel and aluminium. It cnstitutes a technlgical alternative fr a prductin f materials f high dispersin f reinfrcing phases. Eamples f results fr Ni-Al pwders and Ni- Al cmpsite materials prduced by selected reactin synthesis prcess is presented in Table 1. AIM AND SCOPE OF INVESTIGATIONS The main aim f present studies was the verificatin f the technlgy prcedures thrugh the chemical and phase cmpsitin analysis f the pwders f the phases frm Ni-Al system and cmpsite pwders f these phases mdified by ceramic phases. The preparatin f X- ray standards were necessary fr a quick phase analysis f synthesized, mdified r cmpsite pwders with desired intermetallic phases. Fr the realisatin f the assumed gal f studies the fllwing scpe f investigatins was chsen: pwder preparatin f intermetallic phases frm the Ni-Al system as well as a preparatin f cmpsite pwders, analysis f chemical and phase cmpsitins f the synthesised pwders, determinatin f the pwders mrphlgy. MATERIAL AND EXPERIMENTAL PROCEDURE Pwders frm Ni-Al system f definite chemical cmpsitin were prepared. The methd f allys atmisatin and self-develping, high-temperature synthesis were applied fr the preparatin f these pwders. The 1 dr inż., 2 dr hab., 3 mgr inż.
274 B. Frmanek, L. Pająk, B. Szczucka-Lasta TABLE 1. Characteristics f intermetallic NiAl phases frmed by reactive prcesses TABELA 1. Charakterystyka faz NiAl trzymanych za pmcą reaktywnych metd 1 2 3 4 5 6 N. Chemical cmpsitin Ni-at% Al Prcess Cnditins Phase cmpsitin Ref. SRS SHS Flaky Ni pwder Al pwder,9 kms 1 impact 1,37 kms 1 impact 1,6 kms 1 impact GD - 54% GD - 72% GD - 8% Ni 3Al, Ni, NiAl, NiAl, Ni 2Al 3, Ni 3Al NiAl Ni, Ni 3Al, Al rich NiAl Ni 3Al, Al rich NiAl Ni 3Al 7 RI T - 173 K, P - 41 MPa Ni 3Al [5] [3] [4] 8 9 mlten Al mlten Al PC 55% D Ni perfrm 5 MPa 66% D Ni perfrm T - 873 K NiAl,Ni 3Al Ni 3Al [6] 1 11 12 13 4Al 5Al 5Al 15 3 TiB 2 RHP T - 973 K, T - 1173 K, T - 1173 K, T - 163 K, P - 1 GPa P - 3 GPa P - 3 GPa P - 2 GPa NiAl, Ni 3Al, Ni 2Al 3, [7] NiAl-Ni 3Al, Ni 2Al 3 TiB 2 Ni 3Al NiAl TiB 2 NiAl Ni 3Al Ni 2B, Al 2B, NiT 2, 14 49Al15 NiAl15TiB 2 RS T - 973, vacuum NiAl, TiB 2 [8] SRS SHS RI PC RHP RS shck-inducted reactin synthesis self-prpagating high temperature synthesis reactin infiltratin pressure casting high-pressure reactin sintering reactin ht pressing reactin synthesis studies n Ni 5 Al, Ni 3 Al, NiAl, Ni 3 Al 2 -NiAl, NiAl- -Al 2 O 3, NiAl-Al 2 O 3 -AlN were perfrmed. The micrstructure f etched pwder samples was determined by Reichert MF-2 light micrscpe whereas pwders mrphlgy n Hitachi 42 scanning micrscpe. The phase cmpsitin f pwders was analysed frm X-ray diffractin patterns taken n Philips diffractmeter equipped with cpper tube and graphite mnchrmatr n a diffracted beam. The chemical cmpsitin f pwders was determined by means f the EDX methd using the vyager system and the equipment f a scanning micrscpe. phase is the results f the high energy mill preparatin cnditins. The chemical cmpsitin estimated by EDX methd and mrphlgy f pwders is presented is given in Table 2 and in Figures 6 and 7 respectively. TABLE 2. The chemical cmpsitin f NiAl pwders TABELA 2. Skład chemiczny prszku kmpzytweg NiAl Al (wt. %) Ni (wt. %) NiAl 7/3 27.52 69.74 NiAl 95/5 4.64 95.36 Oygen - 2.74 RESULTS Traya prcedure [9] f whle pwder pattern fitting (WPPF) was applied fr testing f the quality f the eperimental patterns. Gd agreement between eperimental and calculated patterns was btained (Figs 1-4). Mrever Traya prcedure enabled the finding f the secnd NiAl phase beside Ni 2 AL 3 ne (Fig. 4). The cmple pwder prepared by SHS methd is f cmple cmpsitin and cntain NiAl, NiAL 3, Al 2 O 3, Ni 2 Al 3, AlN, FeO phases (Fig. 5). The presents f FeO CONCLUSION Pwders f phases frm the Ni-Al system have a different mrphlgy depending n their preparatin methd. A verificatin f a phase cmpsitin f pwders frm X-ray diffractin patterns indicates that the technlgical parameters f the pwder preparatin were crrectly chsen. Preparatin f cmpsite pwders f Ni-Al phases with a definite vlume fractin f ceramic phases is cnnected with beying f a prper prcedure and technlgical parameters. The selected pwders f definite chemical and phase cmp-
5 1 2 3 4 5 6 7 8 9 1 Structure f pwders frm Ni-Al system and these mdified by ceramic phases 275 sitins are destined fr spraying f bnd catings r f catings with intermetallic phases f nickel and higher cncentratin f aluminium. 65 55 45 -NiAl 35 25 15 5-5 2 3 4 5 6 7 8 9 1 11 12 13 14 Fig. 1. X-ray diffractin pattern f NiAl 95-5 pwder Rys. 1. Rentgengram prszku NiAl 95-5 8 7 6 5 4 3 2 1 - Ni3Al 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 Fig. 2. X-ray diffractin pattern f Ni 3Al pwders Rys. 2. Rentgengram prszku Ni 3Al 65 55 45 -NiAl 35 25 15 5-52 3 4 5 6 7 8 9 1 11 12 13 14 Fig. 3. X-ray diffractin pattern f NiAl pwders Rys. 3. Rentgengram prszku NiAl Fig. 4. X-ray diffractin pattern f Ni 2Al 3 pwders Rys. 4. Rentgengram prszku Ni 2Al 3
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