Multilayer ceramic electronic component

1. A multilayer ceramic electronic component comprising:

a ceramic body including an active portion having dielectric layers and first and second internal electrodes alternately stacked with each of the dielectric layers interposed therebetween and first and second cover portions disposed on opposite surfaces of the active portion in a stacking direction, respectively; and

a first external electrode connected to the first internal electrodes and a second external electrode connected to the second internal electrodes,

wherein when a region of the cover portion in contact with the first or second internal electrode is an inner region of the cover portion, and a region of the active portion in contact with the inner region of the cover portion is an outer region of the active portion, 1.00<X A /X B ≤1.04 in which X A /X B is a ratio of a molar ratio (X A ) of barium (Ba) to titanium (Ti) in the inner region of the cover portion to a molar ratio (X B ) of barium (Ba) to titanium (Ti) in the outer region of the active portion.

2. The multilayer ceramic electronic component of claim 1 , wherein the inner region of the cover portion includes crystal grains of a component of the dielectric layers, and

an average grain size of the crystal grains in the inner region of the cover portion is in a range of 140 nm or more and 200 nm or less.

3. The multilayer ceramic electronic component of claim 2 , wherein a dispersion of grain sizes of the crystal grains in the inner region of the cover portion is in a range of 50 nm or more and 80 nm or less.

4. The multilayer ceramic electronic component of claim 1 , wherein the outer region of the active portion includes crystal grains of a component of the dielectric layers, and

an average grain size of the crystal grains in the outer region of the active portion is in a range of 130 nm or more and 230 nm or less.

5. The multilayer ceramic electronic component of claim 4 , wherein a dispersion of grain sizes of the crystal grains in the outer region of the active portion is in a range of 50 nm or more and 100 nm or less.

6. The multilayer ceramic electronic component of claim 1 , wherein the inner region of the cover portion and the outer region of the active portion include crystal grains of a component of the dielectric layers, and

an average grain size of the crystal grains in the inner region of the cover portion is greater than or equal to that of the crystal grains in the outer region of the active portion.

7. The multilayer ceramic electronic component of claim 6 , wherein the average grain size of the crystal grains in the outer region of the active portion is 0.6 times or more and 1.0 times or less the average grain size of the crystal grains in the inner region of the cover portion.

8. The multilayer ceramic electronic component of claim 1 , wherein the inner region of the cover portion includes a main component represented by (Ba 1-x Ca x ) (Ti 1-y (Zr, Sn, Hf) y )O 3 (here, 0≤x≤1 and 0≤y≤0.5) and an accessory component including barium (Ba).

9. The multilayer ceramic electronic component of claim 8 , wherein a molar ratio of barium (Ba) in the inner region of the cover portion to titanium (Ti) in the inner region of the cover portion is in a range of 1.020 or more and 1.040 or less.

10. The multilayer ceramic electronic component of claim 1 , wherein the first and second internal electrodes include one or more conductive metals selected from the group consisting of silver (Ag), palladium (Pd), gold (Au), platinum (Pt), nickel (Ni), copper (Cu), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof.

11. The multilayer ceramic electronic component of claim 1 , wherein X A /X B is 1.035 or less.

12. The multilayer ceramic electronic component of claim 1 , wherein X A /X B is 1.030 or less.

13. The multilayer ceramic electronic component of claim 1 , wherein X A /X B is 1.025 or less.

14. The multilayer ceramic electronic component of claim 1 , wherein X A /X B is 1.020 or less.