CN100415681C - ZnO-Bi2O3 pressure-sensitive ceramic dielectric doped with rare-earth oxide - Google Patents

Abstract

The present invention discloses a ZnO-Bi2O3 voltage sensitive ceramic dielectric doped with rare-earth oxides, which comprises the following components according to the mol percentage: 91% to 98% of ZnO, 0.1% to 1.0% of Bi2O3, 0.1% to 1.0% of Cr2O3, 0.1% to 1.0% of Co2O3, 0.1% to 1.0% of Ni2O3, 0.1% to 1.0% of MnCO3, 0.1% to 1.0% of SiO2, 0.01% to 0.2% of H3BO3, 0.001% to 0.01% of Al (NO3) 3.9H2O and 0.5% to 2% of Sb2 O3. The rare-earth oxides are Ce2 O3 or Gd2 O3, and the content of the Ce2 O3 or the Gd2 O3 is from 0.1% to 1.0%. The ceramic dielectric of the present invention is obtained through single doping work and double doping work for the rare-earth oxides (Ce2O3 or Gd2O3) which are sintered at 1100 to 1180 DEG C and adjusting the reasonable proportion of doping contents, and the potential gradient can be increased to more than 500 V/MM. The voltage sensitive ceramic dielectric of the present invention can be used for making arrester products of good quality of super high-voltage electric power systems.

Description

A kind of ZnO-Bi of doped with rare-earth oxide 2O 3The series pressure-sensitive ceramic medium

Technical field

The present invention relates to a kind of ZnO-Bi ₂O ₃Series pressure-sensitive ceramic medium, particularly a kind of doped with rare-earth oxide ZnO-Bi ₂O ₃The series pressure-sensitive ceramic medium.

Background technology

Improve ZnO-Bi ₂O ₃The conventional method of series pressure-sensitive ceramic electric potential gradient is the size that reduces ZnO crystal grain.If at ZnO-Bi ₂O ₃An amount of rare earth oxide mixes in the series pressure-sensitive ceramic, rare earth oxide or its formed grain boundaries that exists only in mutually, play significant " pinning " effect, obviously suppressed the growth of ZnO crystal grain, the ZnO crystallite dimension is dropped to about 5 μ m, thus corresponding electric potential gradient value can reach 400V/mm or more than.So doped with rare-earth oxide is to ZnO-Bi ₂O ₃Series pressure-sensitive ceramic carries out modification, is a kind of important method that improves the ceramic dielectric electric potential gradient.

At present, the emphasis about doped with rare-earth oxide mainly concentrates on the kind of additive to traditional Z nO-Bi ₂O ₃In the research of series pressure-sensitive ceramic microstructure impact, and for rare earth oxide doped and modified ZnO-Bi ₂O ₃The composition of series pressure-sensitive ceramic has had no open report.All can affect the raising of ceramic dielectric electric potential gradient and the improvement of comprehensive electrochemical properties if additive types is selected improper or addition is improper.

Summary of the invention

The objective of the invention is provides a kind of ZnO-Bi of doped with rare-earth oxide on the basis that the traditional pressure sensitive pottery forms ₂O ₃The composition of series pressure-sensitive ceramic prescription by conventional preparation method, can significantly improve the electric potential gradient of ceramic dielectric behind the sintering, improves the Universal electric performance.

For reaching above purpose, the present invention takes following technical scheme to be achieved:

A kind of ZnO-Bi of doped with rare-earth oxide ₂O ₃The series pressure-sensitive ceramic medium, by mole%, comprise that following component: ZnO is 91～98%; Bi ₂O ₃, Cr ₂O ₃, Co ₂O ₃, Ni ₂O ₃, MnCO ₃And SiO ₂Respectively be 0.1～1.0%; H ₃BO ₃Be 0.01～0.2%, Al (NO ₃) ₃9H ₂O is 0.001～0.01%; Sb ₂O ₃Be 0.5～2%; Rare earth oxide Ce ₂O ₃Or Gd ₂O ₃Content be 0.1～1.0%.

In the above-mentioned composition, component ZnO is preferably 94～97%; B component i ₂O ₃, Cr ₂O ₃, Co ₂O ₃, Ni ₂O ₃, MnCO ₃And SiO ₂Preferably respectively be 0.3～0.7%; Component H ₃BO ₃Be preferably 0.05～0.1%, component Al (NO ₃) ₃9H ₂O is preferably 0.002～0.006%; Component S b ₂O ₃Be preferably 0.7～1.2%; Rare earth oxide Ce ₂O ₃Or Gd ₂O ₃Be 0.3～0.7%; Preferably both have, and respectively be 0.3～0.7%.

Doped with rare-earth oxide ZnO-Bi provided by the present invention ₂O ₃The composition of series pressure-sensitive ceramic medium, by the adjustment to each additive component content, and to rare earth oxide Ce ₂O ₃, Gd ₂O ₃The single doping and the codope test, and the rational proportion of adjustment doping content, the series ceramic medium that obtains at 1100～1180 ℃ of sintering, electric potential gradient is mostly more than 450V/mm, reach as high as 520V/mm, leakage current and nonlinear exponent Universal electric performance indications are also fairly good simultaneously, and doping vario-property has obtained satisfied good effect.Pressure-sensitive ceramic dielectric of the present invention can be used for making the high-quality thunder arrester product of ultra-high/extra-high voltage power system.

Embodiment

The present invention is described in further detail below in conjunction with specific embodiment:

A kind of ZnO-Bi of doped with rare-earth oxide ₂O ₃The series pressure-sensitive ceramic medium, by mole%, comprise that following component: ZnO is 91～98%; Bi ₂O ₃, Cr ₂O ₃, Co ₂O ₃, Ni ₂O ₃, MnCO ₃And SiO ₂Respectively be 0.1～1.0%; H ₃BO ₃Be 0.01～0.2%, Al (NO ₃) ₃9H ₂O is 0.001～0.01%; Sb ₂O ₃Be 0.5～2%; Rare-earth oxide additives Ce ₂O ₃, Gd ₂O ₃Have at least a kind of; Described Ce ₂O ₃, Gd ₂O ₃Content respectively is 0.1～1.0%.List in table 1 concrete the composition, forms totally 18 of A～R.

Additive B i during the present invention forms ₂O ₃, its average grain diameter is at 1～10 μ m, and content is preferably between 0.3～0.7mol% between 0.1～1mol%, and content is crossed to hang down and will be caused the increase of leakage current and the reduction of nonlinear exponent; And too high levels will produce a large amount of pores because of volatilization.Additive Sb during the present invention forms ₂O ₃, its average grain diameter is 0.5～3 μ m, content is adjusted in 0.5～2.0mol% scope, is preferably in 0.75～1.2 scope to adjust Sb ₂O ₃Can improve electric potential gradient, improve the distribution of other additives in porcelain body, Sb ₂O ₃Content is crossed to hang down the homodisperse effect of additive can not be brought into play; And the too high ZnO crystal grain that will cause is too little, and this will affect the through-current capability of big electric current.Addition of C r during the present invention forms ₂O ₃, Co ₂O ₃, MnCO ₃, Ni ₂O ₃, its average grain diameter is between 1～10 μ m, and each constituent content is adjusted in 0.1～1mol% scope, is preferably in 0.3～0.7mol% scope to adjust.

Table 1

Additive SiO during the present invention forms ₂, its average grain diameter is between 0.3～1 μ m, and content is adjusted in 0.1～1mol% scope, is preferably in 0.3～0.7mol% scope to adjust.Additive H ₃BO ₃Content in 0.01～0.2mol% scope, adjust, be preferably between 0.05～0.1mol% and adjust.Additive A l (NO ₃) ₃9H ₂The content of O is lower, adjusts in 0.001～0.01mol% scope, is preferably in 0.002～0.006mol% scope to adjust.The present invention also is doped with rare earth oxide Ce in forming ₂O ₃Or Gd ₂O ₃, its average grain diameter is between 0.5～3 μ m, and content is adjusted in 0.1～1mol% scope, preferably both has, and each adjusts content in 0.3～0.7mol% scope; Doping content is excessively low, can not play the effect that suppresses the ZnO grain growth; Doping content is too high will to cause the decline of nonlinear exponent and the increase of leakage current.

The ZnO-Bi of above-mentioned doped with rare-earth oxide ₂O ₃The preparation method of series pressure-sensitive ceramic medium comprises the steps:

1) form A～R by table 1 and carry out the proportioning weighing, it is pure that the binder component that is adopted is reagent, and major ingredient ZnO is the technical pure of piezoresistor special use, and its median size is about 0.5 μ m.

2) after each composition and ratio weighing, respectively will be except ZnO, Al (NO ₃) ₃9H ₂All components mixing and ball milling beyond the O 20 hours is warming up to 900 ℃ of pre-burnings 30 minutes after 120 ℃ of oven dry.

3) component after the pre-burning is through pulverizing and ZnO, Al (NO again ₃) ₃9H ₂O mixes, and the polyvinyl alcohol water solution ball milling that adds 1wt% concentration was made slurry in 20 hours, then spray-dried one-tenth granulation material;

4) use the single-column press, be pressed into the disk shape green compact that are of a size of φ 26 * 9mm, form to press 6 for every kind, totally 108 of 18 compositions, binder removal under 450 ℃ ± 20 ℃ temperature together with 50 tons forming pressures.

5) be one group with per two of every kind behind binder removal composition (6), each is at 1100 ℃, and sintering is 4 hours under 1150 ℃ and 1180 ℃ of three temperature, and heating rate is 200 ℃/hour, is cooled to room temperature with 100 ℃/hour speed then; Obtain altogether 54 groups of dense sintering bodies of φ 20 * 8mm size, i.e. 18 embodiment of every kind of corresponding three different sintering temperatures of prescription, totally 54 embodiment by the aluminizing electrode, carry out electric performance test, and get its mean value after the end face polishing.

Table 2 has provided the electric performance test result of 1100 ℃ of agglomerating embodiment 1～18:

Table 2

Sample	Form	Potential gradient (V/mm)	Leakage current (μ A)	Nonlinear exponent
					Embodiment 1	A	280	0.5	35
Embodiment 2	B	278	0.2	36
					Embodiment 3	C	277	0.2	35
Embodiment 4	D	315	55	8
					Embodiment 5	E	360	45	10
Embodiment 6	F	346	27	9
					Embodiment 7	G	460	15	15
Embodiment 8	H	480	13	14
					Embodiment 9	I	482	13	12
Embodiment 10	J	490	16	12
					Embodiment 11	K	500	18	13
Embodiment 12	L	508	17	12
					Embodiment 13	M	500	18	12
Embodiment 14	N	510	20	11
					Embodiment 15	O	520	20	11
Embodiment 16	P	479	21	9
					Embodiment 17	Q	465	21	9
Embodiment 18	R	470	23	8

Table 3 has provided the electric performance test result of 1150 ℃ of agglomerating embodiment 19～36:

Table 3

Sample	Form	Potential gradient (V/mm)	Leakage current (μ A)	Nonlinear exponent
					Embodiment 19	A	250	0.3	40
Embodiment 20	B	246	0.2	42
					Embodiment 21	C	245	0.2	39
Embodiment 22	D	316	45	12
					Embodiment 23	E	335	35	14
Embodiment 24	F	341	35	13
					Embodiment 25	G	456	12	19
Embodiment 26	H	476	11	18
					Embodiment 27	I	478	11	16
Embodiment 28	J	487	12	16
					Embodiment 29	K	450	13	17
Embodiment 30	L	455	12	16
					Embodiment 31	M	485	13	16
Embodiment 32	N	486	15	15
					Embodiment 33	O	486	15	15
Embodiment 34	P	435	16	13
					Embodiment 35	Q	432	16	13
Embodiment 36	R	436	18	12

Table 4 has provided the electric performance test result of 1180 ℃ of agglomerating embodiment 37～54:

Table 4

Sample	Form	Potential gradient (V/mm)	Leakage current (μ A)	Nonlinear exponent
					Embodiment 37	A	200	0.3	45
Embodiment 38	B	198	0.2	45
					Embodiment 39	C	198	0.3	44
Embodiment 40	D	257	45	15
					Embodiment 41	E	258	35	16
Embodiment 42	F	271	35	16
					Embodiment 43	G	445	12	25
Embodiment 44	H	450	11	24
					Embodiment 45	I	451	11	24
Embodiment 46	J	450	12	22
					Embodiment 47	K	452	13	23
Embodiment 48	L	455	12	22
					Embodiment 49	M	455	13	22
Embodiment 50	N	460	13	22
					Embodiment 51	O	460	15	21
Embodiment 52	P	410	16	19
					Embodiment 53	Q	406	16	19
Embodiment 54	R	405	18	18

Can find out from table 2, table 3, table 4 test result, form G～O at 1100 ℃ of agglomerating embodiment 7～15, at 1150 ℃ of agglomerating embodiment 25～33, at 1180 ℃ of agglomerating embodiment 43～51, all more than 450V/mm, embodiment 15 is up to 520V/mm for potential gradient; All below 20 μ A, nonlinear exponent is all more than 11 for leakage current, and embodiment 43 is up to 25; Integrated performance index is fairly good.

Claims (3)

1. the ZnO-Bi of a doped with rare-earth oxide ₂O ₃The series pressure-sensitive ceramic medium is characterized in that, by mole%, comprise that following component: ZnO is 91～98%; Bi ₂O ₃, Cr ₂O ₃, Co ₂O ₃, Ni ₂O ₃, MnCO ₃And SiO ₂Respectively be 0.1～1.0%; H ₃BO ₃Be 0.01～0.2%, Al (NO ₃) ₃9H ₂O is 0.001～0.01%; Sb ₂O ₃Be 0.5～2%; Rare earth oxide Ce ₂O ₃, Gd ₂O ₃One or both, its content respectively is 0.1～1.0%.

2. the ZnO-Bi of doped with rare-earth oxide according to claim 1 ₂O ₃The series pressure-sensitive ceramic medium is characterized in that, by mole%, comprise that following component: ZnO is 94～97%; Bi ₂O ₃, Cr ₂O ₃, Co ₂O ₃, Ni ₂O ₃, MnCO ₃And SiO ₂Respectively be 0.3～0.7%; H ₃BO ₃Be 0.05～0.1%, Al (NO ₃) ₃9H ₂O is 0.002～0.006%; Sb ₂O ₃Be 0.7～1.2%; Rare earth oxide Ce ₂O ₃, Gd ₂O ₃One or both, its content respectively is 0.3～0.7%.

3. the ZnO-Bi of doped with rare-earth oxide according to claim 2 ₂O ₃The series pressure-sensitive ceramic medium is characterized in that, described rare earth oxide is Ce ₂O ₃And Gd ₂O ₃Two kinds, its content respectively is 0.3～0.7%.