Aal : 
(Mn, 9) CuMn,O, NiMn, O, 
PR PM 2 N rn 
CuMn, ©, / A fin ofA a | 
? nv u 6. Oo 
; A 7 40 | W.10% 69 % 
| "N\MnCo,0, & “N eo 
P= 60 40 
SY A § ’ “u % 
cu > A Ni GE 
(CuO) X. (NiO) 80 1 20 (uv 
’ re 4 | | 
2% | . 
-- --4 MnCo0, 20 40 60 80 NiMnO, Co 
(CoO,Co,O,) NiMn,O, (mole %) a 
Fig.1: Selected section of Cu-Ni-Co-Mn oxide Fig.2: Isolines of electrical conductivity at 
system: 1- region of existence of (Cu,Ni)Mn2O4 298 K for semiconducting ceramics of Cie 
solid solutions; 2 - region of existence of Cu,Ni1.-x-yCo2yMn2.,O4 system 
(Ni,Mn,Co0)304 solid solutions; 3 - region of 
existence of (Cu,Mn,Co)3;04 solid solutions; 4 - Ci: oi 
chosen ceramic compositions. 
Ci: Nin 
Results and Discussion N 
Influence of sintering temperature on the structure of Cu,Ni;.x.yCozyMnz.,O4 semiconducting Cur 
ceramics is demonstrated in table 1. The following abbreviations are used: SS - solid solution, SPSS 
- single phase solid solution, TO - traces of oxides; DPSSVC - double phase solid solution of = 
variable composition, CMC - complex multiphase composition, CMOC - complex multiphase oxide Cu 
composition, DPSS - double phase solid solution; DPC - double phase composition, DPCSS - | 
double phase composition of solid solutions; SSMIAPIB - solid solution with microscopic = 
inclusions of additional phases and intergrain boundaries. 
As it is known the application of salts for the synthesis of ceramic semiconducting compositions 
permits to obtain the powder materials with high degree of dispersivity and able to be sintered at the C 
temperatures near 0.57, 
For Cu,Ni).xyCo2yMn,.yO4 system we established that at sintering temperature 7 from the range 1 oo 
((0.5-0.75)T,,) ceramics have low density, low mechanical strength and medium dimensions of 
grains. As we can see on the sample of Cug2NigCo1.4Mn; 304 composition (fig.3a) the structure is 
characterized by a large number of pores at the points where crystallites touch one with another. . 
These pores look as communicating channels and closed regions while pores are absent inside of 
crystallites. Such ceramic samples are very inconvenient for mechanical treatment (polishing, 
grinding) because of intensive coming out of crystallites from surface layer of ceramics. It means 
that on this stage only sintering of separate crystallites takes place resulting in the formation of 
crystallite grid, where every component have structural individuality. It was confirmed by the 
method of X-ray phase analysis that at these temperatures along with solid solutions with spinel 
structure the inclusions of Ni, Mn, Co and Cu oxides are present and grains are characterized by = 
inhomogeneity of cationic composition. These oxides are undesirable for thermistor manufacturing. Bo 
Ar CuMn,O, 
2710